You can earn this credit simply by eliminating turf grass, planting native and adaptive species, and not installing an irrigation system. If those measures go too far for your project, you can still achieve the credit as long as you have some flexibility with plant species selection, and irrigation system design and controls. You may need a landscape designer to identify local or adaptive plant species that require little irrigation, to design water-efficient irrigation systems, to address the potential use of non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems., and to reduce irrigation needs through zoning, grouping, and grading of the landscape.
If you do install irrigation, you must perform calculations to show the savings of the project design versus a baseline. Usually done by the landscape architect or architect, these calculations determine the percent reduction of total water applied and total potable water applied.
No, non-potable groundwater used for irrigation (other than nuisance groundwater, i.e. water pumped away from a foundation) is considered a potential potable source and would not count towards Option 2.
The baseline and design cases are the same, and they are based on the total irrigated area in the design case.
For any project, the minimum is 5% of site area. This can include planters.
Yes, if it is irrigated and not considered in its natural state.
Although this may contribute to reducing irrigation demand, this does not help with achieving the credit, as landscaped area in the both the baseline and design case has to be the same. Although decreasing vegetated space may be a sensible option for some projects, it is not allowed to contribute to this credit. It would not match the intent of this and other credits for LEED to include an incentive to reduce vegetated area.
The LEED-NC v2.2 requirements is for no more than 12 months. According to a LEED Reference Guide addendum from 7/19/2010, the time period was been increased from 12 months to 18 months for LEED 2009 projects, but USGBC has not altered the timeframe for pre-2009 projects.
LEED does not distinguish what characteristics make an irrigation system "temporary." However, teams have had success by installing irrigation systems with plans to disable them in some way, such as removing sprinkler heads, cutting up pipe, or causing some other severe, if not unalterable, damage to the system.
Eliminating turf grass, planting native and adaptive species, and not installing an irrigation system is the simplest and cheapest way to achieve this credit. It will also have several additional environmental and financial benefits not necessarily recognized by LEED, such as reducing mowing costs, energy use, emissions, pesticide and fertilizer needs, and maintenance. Start by evaluating this option, taking into account the owner’s expectations, the climate, and site conditions.
Lawn as the default landscape planting doesn't make sense in dry climates, where its lushness can only be maintained at the cost of frequent watering. Xeriscaping such as shown here, using native and drought-resistant plants, is a better choice. Las Vegas Valley Water DistrictEvaluate the project’s landscaping needs and develop water savings goals. Consider opportunities to use native or adapted vegetationAdapted (or introduced) plants reliably grow well in a given habitat with minimal winter protection, pest control, fertilization, or irrigation once their root systems are established. Adapted plants are considered low maintenance and not invasive. to reduce irrigation needs. Look for all water sources on the site, such as stormwater, graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area., treated wastewater, and note opportunities for using that water for irrigation. Include water savings goals in the Owner’s Project Requirements (OPROwner's project requirements (OPR) is a written document that details the ideas, concepts, and criteria that are determined by the owner to be important to the success of the project.) for EAp1: Fundamental Commissioning.
Using alternative water sources for irrigation may add costs compared with conventional irrigation. For example, a rainwater cistern will be an added cost, and space must be found for it. However, this may lead to cost reductions in other areas, such as reduced stormwater retention infrastructure, or lower water and sewer costs.
Research native or drought-tolerant plants and efficient irrigation systems and controls. Check for local incentives for efficient systems and controls.
Evaluate the potential for nonpotable waterNonpotable water: does not meet EPA's drinking water quality standards and is not approved for human consumption by the state or local authorities having jurisdiction. Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents. sources, including rainwater reuse and graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. reuse. If non-potable water use seems feasible for your project evaluate the water demand for your landscape and the quantity of water reuse available to your project. Calculations, usually done by the landscape architect, have to account for annual rainfall on a monthly basis for the project location. Rainwater, which may need basic filtration but not usually additional treatment, can be piped directly to plantings to reduce the need for potable irrigation water. Evaluate the potential for graywater. Research graywater or rainwater regulations, and local incentives. Check with local authorities on acceptable rainwater and graywater capture, collection, and reuse methods. Local codes may place limits on some uses of alternative water supplies. Develop a water budget, both project-wide and for landscape irrigation.
Work with the whole project team to evaluate synergies and tradeoffs with other LEED credits or green building strategies. These may include using rain gardens for stormwater infiltration, trees for shading the building and hardscapes for cooling-load reduction, porous surfaces, soil selection encouraging infiltration, windbreaks, water reuse, rainwater capture and acoustical barriers.
The following water sources count as reused for credit purposes: graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. (lavatory, sink and shower water), harvested rainwater (cistern, underground, or pond), nuisance water (water that must be pumped away from the building), treated wastewater, air-conditioner condensate, reverse-osmosis reject, and sump-pump water. All well water is counted as potable for credit purposes.
Starting the LEED calculations early, along with early completion of a compliant landscape design can avoid costly redesign due to non-compliance.
For WEc1.2: No Potable WaterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. Use or No Irrigation, projects have to achieve a 50% reduction in total water applied in addition to eliminating irrigating with potable water. That is, even if a project uses non-potable water for irrigation, it must also reduce the total water use for irrigation by 50%. To use non-potable water to pursue WEc1.2, projects must provide a detailed narrative on the actual source and available quantity of the non-potable water as well as the anticipated schedule for implementation of the non-potable system.
You can avoid submitting calculations for credit compliance by not using permanent irrigation. In this case, no permanent irrigation system can be installed, even with the intent to turn it off. Irrigation for plant establishment, allowable for one year, must be manual, or through temporary, above-grade systems. Using hose bibs to water when plants are being established and during drought conditions is allowed as “temporary irrigation.”
Look for local incentives for sub-grade irrigation, efficient irrigation, irrigation controls, and/or irrigation sub-metering. For example, one city provides up to $7,000 per acre-foot of water saved, and another program provided rebates up to $1,000 per acre for weather-based irrigation controls. Some municipalities even support “cash for grass” programs that provide rebates for the replacement of turf and with native plantings. For example, one pilot program provides $1.00 per square foot of replaced turf grass.
Evaluate a number of scenarios to achieve the credit. Look for options that work best for the design, and see if there are any trade-offs or overlaps with other LEED credits.
If irrigation is necessary, drip irrigation is a water-efficient way to deliver it where it is needed, with minimal evaporative losses. City of San Luis Obisbo Utilities DepartmentDesign landscape and irrigation systems to maximize native and adapted species, use efficient irrigation technology, and reuse water where possible. Evaluate the different irrigation technologies for their efficiency and suitability to the project. These include subsurface, bubbler, drip, and rotor sprinkler. Installing weather controls or soil moisture sensors can greatly reduce unnecessary irrigation. Consider directing rainwater to planting beds to reduce the need for potable irrigation water.
Detailed calculations to demonstrate irrigation efficiency will be required from the landscape architect. The study “Performance and Water Conservation Potential of Multi-Stream, Multi-Trajectory Rotating Sprinklers for Landscape Irrigation” (see Resources) provides expected water conservation percentages derived from measured data. Efficiency ratings provided by manufacturers for irrigation components and controls can be used for calculations, but most manufacturers do not provide this data, so you’ll need additional calculations.
Use of drip irrigation helps to conserve water. BuildingGreen ImageThe design cost of a drip irrigation system is generally comparable to a standard system. However, installation might be more expensive for drip irrigation, particularly as plant density increases.
The landscape architect calculates the potential for rainwater reuse and corresponding cistern sizes to accommodate landscape and other rainwater reuse applications. Calculations must account for annual rainfall of the project location.
There are fewer codes and associated costs for collecting and using rainwater for irrigation than for interior water reuse. Harvested rainwater can often be reused for irrigation purposes with minimal treatment, although filtration is usually needed.
The mechanical engineer calculates the potential for graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. reuse and applicable treatment methods.
Perform LEED calculations using the LEED Online calculator to evaluate compliance. Only “softscape” areas are included in calculations. Projects that replace landscape irrigation with hardscapeHardscape consists of the inanimate elements of the building landscaping. Examples include pavement, roadways, stone walls, concrete paths and sidewalks, and concrete, brick, and tile patios. to reduce irrigation needs cannot count this area in their calculations.
The landscape architect develops a baseline outdoor-water-use calculation based on mid-summer (July) and compares that to a calculation for the planned project design case water use (also for July). The difference is the percent reduction and identifies credit achievement. Factors included in the calculations are: plant species, density, microclimate, evapotranspiration rate, irrigation efficiency,, and non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use, and controller efficiency (gains from controller efficiency cannot exceed 30% in July). The local project baseline case is a subjective calculation that will vary by city and is based on standard practice in that region. The landscape design case is created by setting the irrigation variables to values representative of the actual designed landscape plan. The landscape water efficiency boundary used must be the same project boundary used for all other LEED credits. (See the documentation toolkit for more information.)
The landscape architect runs final outdoor water use calculations for the project’s design case annual water usage. These calculations should confirm that the landscape water reduction goals are met. If the goals are not met, adjust the landscape and irrigation design as needed.
The landscape architect provides LEED documentation for submittal to LEED Online.
The commissioning agent commissions irrigation and water reuse systems to ensure they operate as designed.
Create a maintenance plan to ensure ongoing, as-designed performance of irrigation systems and equipment. Doing so will also contribute to LEED-EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems. credit compliance. Along with the maintenance plan, provide product manuals for irrigation systems including weather and moisture controls to maintenance personnel, and discuss irrigation and planting maintenance needs. When operational, verify that the sprinkler system is not spraying the building, to avoid water waste, mold and termite damage. Also avoid wasting water spraying on other hardscapeHardscape consists of the inanimate elements of the building landscaping. Examples include pavement, roadways, stone walls, concrete paths and sidewalks, and concrete, brick, and tile patios. surfaces like roads and sidewalks.
Minimize irrigation frequency in an effort to conserve water. Apply irrigation at the lowest rate required to keep plants healthy. New plants may need to be irrigated more, in order to establish them. Change irrigation schedules on a regular basis to adjust for seasonal variations in watering needs, including turning them off in the fall. Use an irrigation system that is tied directly to weather forecasts, or manually program irrigation clocks weekly or more often, based on projected rainfall and weather patterns.
Incorporating mulch and using mulching mowers will help keep moisture in the soil, and reduce irrigation needs. Adding compost to the soil will help maintain plant health over time and aid in moisture retention.
Creating an Integrated Pest ManagementIntegrated pest management (IPM) is the coordinated use of knowledge about pests, the environment, and pest prevention and control methods to minimize pest infestation and damage by the most economical means while minimizing hazards to people, property, and the environment. plan will offer environmental and health benefits, while contributing to the ongoing attractiveness of the landscape. Doing so will also contribute to LEED-EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems. credit compliance.
Installing a sub-metering system for irrigation water can help operators monitor water usage and detect problems early on. Doing so will also contribute LEED-EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems. credit compliance.
The cost of maintenance will vary depending on the strategy employed. For example, subsurface or drip irrigationDrip irrigation delivers water at low pressure through buried mains and submains. From the submains, water is distributed to the soil through a network of perforated tubes or emitters. Drip irrigation is a high-efficiency type of microirrigation. systems can be more difficult to maintain, because malfunctions are more hidden.
Excerpted from LEED for New Construction and Major Renovations Version 2.2
Limit or eliminate the use of potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems., or other natural surface or subsurface water resources available on or near the project site, for landscape irrigation.
Reduce potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. consumption for irrigation by 50% from a calculated mid-summer baseline case. Reductions shall be attributed to any combination of the following items: ␣
Achieve WE Credit 1.1. and:
Use only captured rainwater, recycled wastewater, recycled greywater, or water treated and conveyed by a public agency specifically for non-potable uses for irrigation.
Install landscaping that does not require permanent irrigation systems. Temporary irrigation systems used for plant establishment are allowed only if removed within one year of installation.
Perform a soil/climate analysis to determine appropriate landscape types and design the landscape with indigenous plants to reduce or eliminate irrigation requirements. Consider using stormwater, greywater, and/or condensate water for irrigation.
ARCSA was founded to promote rainwater catchment systems in the United States. The ARCSA website provides regional resources, publications, suppliers, and membership information.
CIT is an independent research and testing facility that provides information to designers, manufacturers, and users of irrigation equipment.
This nonprofit organization focuses on promoting products that efficiently use water in irrigation applications.
The clearinghouse includes articles, reference materials, and papers on all forms of water efficiency.
The NCDC site is useful for researching local climate information such as data for rainwater harvesting calculations, and it also includes links to state climate offices.
Enter your project latitude and longitude—easily taken from Google Earth—and you will get the ETo for pretty much anywhere on earth. A note of caution: spot checking reveals that data may not be reliable in all locations. Make sure that data such as precipitation and temperatures checks out before using the ETo values proposed by the model.
This free software provides sufficient local evapotranspiration data for the United States and Canada. Access data from the closest or most climate-appropriate location.
This website provides data from the state of Texas regarding water resources and services such as groundwater mapping and water availability modeling. The site also provides brochures on indoor and outdoor water efficiency strategies.
This study provides expected water conservation percentages derived from measured data, which can be used to support water efficiency calculations for this credit.
This manual provides information about reducing water consumption through creative landscaping techniques.
Use a site plan and narrative to approach and document credit compliance, like these examples from the Denver School of Science and Technology Landscape Design.
Use a narrative like this to demonstrate a 50% reduction in potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use.
Use a narrative like one of these to demonstrate no potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use for irrigation, or no irrigation.
This template is the flattened, public version of the dynamic template for this credit that is used within LEED-Online v2 by registered project teams. This and other public versions of LEED credit templates come from the USGBC website, and are posted on LEEDuser with USGBC's permission. You'll need to fill out the live version of this template on LEED Online to document this credit.
Documentation for this credit can be part of a Design Phase submittal.
Is it acceptable to reduce potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. usage by reducing the actual area of landscaping that receives irrigation? In other words, if, fore example, the landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios. is 10,000 SF, consisting of 8,000 SF of seeded area; 1,000 SF of sodded area; and 1,000 SF of vegetated beds; can one elect to omit permanent irrigation in 6,000 SF of the seeded area in the design case? Can that be worked into the calculation to zero out that area, while leaving the landscape area the same for the baseline and design cases?
Lamonte, what you describe is a good idea, but it won't contribute to earning this LEED credit. See the credit language above—reducing the landscaped and/or irrigated area is not a strategy that can be used to comply.
Our project (NC v2.2) uses 100% Public Agency Sourced Non-Potable WaterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. for irrigation. The reviewer is asking for specific information regarding the available quantity of public agency sourced non-potable water. I never saw this comment on any of my other projects using the same public source. Checking the reference guide I don't see where that info is required to be provided. I cannot locate an addenda covering this item. Perhaps I am missing something. Any help would be appreciated.
Sheryl, it sounds like the reviewer wants to know if the water will be a steady source for the project, or if it could easily switch plumbing to take in regular potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems.?
This kind of water source can get some scrutiny from GBCI, and I would simply recommend providing the info they're asking for, or if it's hard to provide, asking for some clarification as to why they want it. Past reviews are not precedent-setting, so I wouldn't lean on them too heavily, but you could reference your LEED project experience using this water source.
I have never done this leed calculation . Is there a site which provides examples and a site which contains a table of evaporation rates for different plant species
We have a site which is currently mostly native vegetationPlants indigenous to a locality (native) and adapted to the local climate; they require limited irrigation following planting, do not require active maintenance such as mowing, and provide habitat value. (has never been altered.) We are planning to preserve the native vegetation, therefore achieving credit SSc5.1.
For this credit (WEc1) do we count only the area of the site that we are actually altering in the baseline and design cases? Or do we use the entire site, including the existing native vegetation as zero water use in the design case but landscaped with shrubs in the baseline case?
Marc, see the second FAQ above—I think this answers your question.
We have a project completed nearly 2 yrs ago that the native turf grass is not performing well.The project has been certified already, with this area contributing to the success of SS5.2 (Open space), SS 6 (stormwater), WE1... Does LEED have guidelines on post certification alterations of areas that contributed to a credit?
Jill, great question. If things aren't working as planned it would be great to make alterations so that things perform as planned. Unless you bring this to GBCI's attention by formally reopening your certification (which I have only heard of being done via an appeals process by someone disgruntled with the project), however, there are no real LEED guidelines for doing this work.
The most constructive path forward in my opinion LEED-wise would be to register for LEED-EBOM and start getting your operations certified.
In the bird's eye view, it is stated:
"What is the minimum required irrigated area that will achieve the credit?
For any project, the minimum is 5% of site area. This can include planters."
I'm not sure I understand. We have a site with less than 1% of the total pervious area receiving permanent irrigation. Does the statement above mean that we cannot achieve the WEc1 credit? This seems counterintuitive. Perhaps this means that anything less than 5% of the site means we are essentially a "No Irrigation" site? This seems to make more sense, but if anyone can help clear this up, it would be much appreciated. Thanks!
- Kris Phillips
This requirement is for buildings without vegetation on the grounds,..teams can earn points by reducing the use of potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. for watering any roof and courtyard garden space or outdoor planters, provided the planters and garden space cover at least 5% of the building site area (including building footprintBuilding footprint is the area on a project site used by the building structure, defined by the perimeter of the building plan. Parking lots, parking garages, landscapes, and other nonbuilding facilities are not included in the building footprint., hardscapeHardscape consists of the inanimate elements of the building landscaping. Examples include pavement, roadways, stone walls, concrete paths and sidewalks, and concrete, brick, and tile patios. area, parking footprintParking footprint refers to the area of the project site occupied by the parking areas and structures., etc.). However, if the planters cover less than 5% of the building site area, the project is ineligible for this credit.
Hope this helps clarify.
Thanks for the reply. That does help. The statement in the bird's eye view seems somewhat random and implies a broader application. Your clarification informs me that this does not apply to my particular project which has nearly 200,000 square feet of vegetation - primarily non-irrigated turf, but with a small area of about 1,000 square feet of landscaped area requiring permanent irrigation. We were hoping for a way out of doing the calculations for such a small area, but it looks like we will have to do them after all. Thanks again - Kris
Based on the reference guide which states that the Baseline case is calculated by setting the Species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species., Density factorDensity factor (kd) is a coefficient used in calculating the landscape coefficient. It modifies the evapotranspiration rate to reflect the water use of a plant or group of plants, particularly with reference to the density of the plant material. and Irrigation Efficiency to average values representative of conventional equipment and design practices. Does this mean I have to use the average value for the Species factor, Density factor and Irrigation Efficiency? Or can I use the values that reflect the conventional equipment and design practices used in my country?
I have submitted not using the average values before but rather what the typical baseline would be reflecting local conventional practices and it was not a problem. But a different project has come back saying that I have to use the average values. It is pretty inconsistent.
Yes, in order to comply with the calculation methodology described in the Calculations section under WEc1 of the LEED Reference Guide for Green Building Design and Construction, 2009 Edition, the baseline case must use the average value for the Species (Ks) and Density (Kd) Factors.
We are in above the 50% requirement for credit WEc 1.1 (ver.2.2) and are considering pursuing 1.2. We have dual cisterns which capture and provide us with the water for irrigation - however we are tied into a potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. line in the event there is a drought.
To achieve WEc 1.2 - will it be necessary to disconnect the back-up potable water line?
I would caution that a potable waterline attached to the permanent nonpotable irrigation system for an emergency-use-only type condition is not an acceptable strategy for achievement of this credit (unless there is a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. I missed that states otherwise), primarily because there is no way to ensure that the potable water system will be disconnected at the end of the emergency-use-only period. As outlined in the LEED BD+C RG, hose bibs are an acceptable strategy that can be used for temporary irrigation during periods of drought. Refer to LEED Interpretations 2207, 5766 and 5962 for similar strategies that are acceptable as a temporary irrigation strategy for this credit.
Thanks for your reply Carlie - very helpful. And thank you for the LEED interpretations references - I'm going to check them out. If I have any more questions I'll head back this way.
I recently was contacted by a consultant who is filling out a LEED form and asked for a “Controller Factor” that is supposedly between 0.7 and 1.0. The inquirer thinks the 1.0 reflects the rating for a standard, non-smart controller. Can you shed any light on this rating system?
1.0 is not controller at all. If a controller saves 10% of the water then your controller efficiency (CE) is 90%, 0.90.
It seems the certification reviewers have turned CE into a math game. It may not longer be safe to use an average savings like Rainbird provides.
Determining the actual CE for a specific project is not something the equipment providers seem to know how to do. Yet, it is sometimes demanded by the reviewers, possibly every time it is claimed based on current review requirements.
I have a method I came up with myself for how to meet the reviewer demand for rain sensors. It requires an annual water use calculation using ETo for an entire year. Here is an example of an annual calculation:
You do not have to do monthly calculations. You will get the same answer using annual ETo and average annual rainfall.
In the calculations provided the assumption is that the rain sensor stops with any amount of rain. This is not the way the sensors work. The stop after a specific amount of water is collected. Stop irrigating values could range from 1/8" to 1".
Assume you set the stop point to 1/4". You need to determine the frequency of rain events under 1/4". For those you do not stop irrigating. For events greater than 1/4" the rainfall greater than 1/4" is saved water. If you determined that 50% of the rain that fell was for events over the 1/4" stop point then you annual water savings is 50% times the average annual rainfall.
I still haven't figured out how to take math-wise credit for soil moisture sensors, or plant-wise smart controllers that can manage per irrigation point.
How is this number obtained? I have specified the Rainbird ETEvapotranspiration (ET) is the loss of water by evaporation from the soil and by transpiration from plants. It is expressed in millimeters per unit of time. Manager, which I've heard is the most efficient irrigation controller on the market, but Rainbird specifically stated to me over the phone that they do not have a specific controller efficiency number. Currently we are in the high 40 percentile for water reduction and the LEED consultant has stressed how important this number could be. Any thoughts?
Thanks Hernando. I am really in the dark on this one so I appreciate your fast reply.
Judging by your link, the ETEvapotranspiration (ET) is the loss of water by evaporation from the soil and by transpiration from plants. It is expressed in millimeters per unit of time. Manager (or like Smart Controller Technologies) give a baseline of 40% water savings... citing case studies having been done in CA. This is my first time trying to procure this sort of data so excuse me if I ask a dumb question, but... the project I am currently working on is in NYC so:
A- Will this data even apply here?
B- How would I begin to use it?
Again, many thanks.
Thank you for your comments, they are very helpful.
Just to clarify, do you use manufacture's documentation or do your own calculation to determine CE?
I have the understanding that LEED instructions focus on a single month for mathematical calculations, the month of July. The example I was sent looks at 10 years of daily ET and rainfall data for the 31 days of July. They assume that the controller will be programmed to deliver sufficient water to handle the hottest week of the month. They then compare that amount of water in inches applied to a smart controller that adjusts the watering times daily to whatever the daily ET demand requires.
Thank you again for your help!
We have a NC 2.2 project that plans to install an irrigation system for plant establishment only and then disable the entire system by cutting a piece of the main line out and capping it. While the first CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide below states all or substantial portions must be removed, our approach completely disables the entire system and reduces subsequent impact removal will have on the new landscape. The second CIR implies that portions of the system being removed that result in disabling it meet the intent.
The owner will provide a letter stating they will cut and cap the line and not irrigate the site in the future.
We believe this strategy meets the credit intent.
A referenced CIR states "...the project team should note the irrigation system installed must be temporary and easily removed. All or substantial portions of the irrigation system must be removed so as to disable the irrigation system after the one year establishment period." (4/22/2009 ID# 2552)
A second CIR says "The project would like to permanently bury the mainline of a temporary irrigation system and remove the rest of the irrigation system within one year of installation. The mainline would remain in place so that quick couplers could be used for hand watering. Although the applicant is proposing to only remove a portion of the irrigation system, the portions that will be removed can be removed easily and this removal will then completely disable the automated irrigation system. Therefore, this strategy meets the intent of the requirement." (6/19/2008 ID# 2207)
You might get through with this strategy, but if I were the reviewer I'd say that is easy to reconnect and not enough to be seen as a permanent disabled system. You might want to argue with destroying the landscape while removing it all or take out more of it to proof this isn't easily reversible.
Did the strategy to cut/cap and provide a letter from the owner work? I have a similar situation where I would like to avoid disturbing the site more than has already occurred. How much more (beyond cut/cap) would I need to remove in order to show the system is disabled?
I thought that I had remembered reading awhile back that the temporary irrigation period allowed per NC v2.2 had been extended to 18 months, but I just browsed through the LEED Intepretations and Addenda and can only find the addenda change from one year to 18 months for NC 2009. Is anyone aware of the 18 month irrigation period applying to v2.2 as well, or should we just inform the owner that the temporary irrigation system will need to be removed within one year (unless the owner is okay with losing WEc1.2)? The owner for our project does not want any permanent irrigation. The project is in San Antonio, and especially given the recent droughts in Texas, the additional six months would be helpful for the future health of the vegetation.
Christine, there are many changes for LEED 2009 that don't apply to v2.2—apparently, this is one of them.
I would do what's best for the project, though. If you need 18 months, take it, and try to explain in a narrative why—maybe it will fly.
Working on a project and trying to determine if planting only turf grass without an irrigation system will be enough for the project to achieve the credit. If this does not meet it, what would the project have to do? Plant a few native/adaptive plants? Thanks
You can do that. I have actually done it on one of our projects. However we also used a different mix of seeds for the turf, so it's more drought resistant to begin with. We also had no other permanent irrigation in place. If it's extremely dry, which at that location rarely happens, the turf just turns yellow. However you will need at least a letter from the landscape architect explaining that your turf can handle it. If you are planning on doing this in Arizona, when I doubt the reviewer will accept that.
Our project currently has water use reduction of 70% for 1 point. The project is utilizing a cistern and well water. The city where the project is located considers well water as non-potable. Can we consider our well water as non-potable for LEED purposes and achieve 100% reduction for 2 points?
Stephen, I believe that USGBC specifically rules out use of well water in the Reference Guide. I believe that for the purposes of LEED this would supersede the city definition. As Emily suggests it may be possible, though.
You may be able to account for the additional reduction. Potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. is defined as water that "...meets or exceeds EPA's drinking water quality standards..." Other users here on LEEDuser posted that they showed non compliance with EPA's standards in order to account for it.
I work for a company that makes a wireless soil moisture sensor technology that has been very successful in reducing outdoor water use. We have many studies showing the water reduction. We are beginning to get inquiries as to how many points our technology can help contribute to LEED certification. My question is this: For those new construction projects that include both irrigated turf and native plants that need no water, are we able to combine our water savings on the turf with the water savings that are obtained by the native plant areas? How long (months?) does a site have to show water savings when compared to the baseline? Thanks for any help!
Depending of the reduction of the potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. demand you can get 1 or 2 points under the LEED NC v2 system and 2or 4 under LEED NC v3. Your irrigation system can not achieve full points without using non-potable water for the irrigation.
For the time period, the reduction is base of a midsummer baseline. So a snap shut of the time with highest demand.
If you want to show the savings of your system than a study of savings based on midsummer conditions is probably most appropriate. I hope that helps.
Hi Susann, on our project we can demonstrate that in mid summer (July) we have enough (+50%) non potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. (condensate + greywater) to sustain for irrigation need. But in winter we will have to use potable water since we are short of condensate water surplus, and greywater alone won't be enough. In this case scenario, can we still pass the credit?
July is representative for the month this the biggest irrigation water demand. As long as you are using the month with the largest irrigation water demand in your location, you should be fine. This is not exactly what the credit was intended to do, but I think you kinda found a loophole here.
The question is doesn't your irrigation water demand decrease in the winter months, just like the amount of condensate?
Correct, in winter we have less condensate water and irrigation demand decreases, but we're still short. So we can use potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. whenever needed as long as the biggest month is covered with non potable water?! So basically we need to prove that we're saving 50% potable water for 1 month of the year only?
You are meeting the credit requirements of LEED v2.2 by doing that.
LEED v2.1 is less specific, which can be interpreted differently.
Anyhow if you are saving more than 50% of the water looking at the whole year, you will be fine for sure. I hope that helps.
How do I include the portion of a site that will have temporary irrigation into the calculations?
Brett, my understanding is that you don't need to do that at all. The temporary irrigation is pretty much ignored since you are on a path to no irrigation.
Thanks Tristin. Most of the site landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios. will be irrigated, but there is a substantial portion that will be natural restoration with tmeporary irrgation. We would like that area to be included in the calculations to meet the 50% irrigation reduction. Is the area still ignore in this instance?
I would count that natural restored area as not irrigated at all, since it's permanent systems that you're modeling for the credit. Make sense?
Thanks Tristan. I think I am confused as to how this can be expressed in the calculation spreadsheet or if it should at all. If the baseline design would have ground cover with average plants, density and micro-climate, how do include this square footage zero TWA thus reducing my percentage compared to the baseline? Thanks for your help.
Brett, can you be more specific about where you're getting hung up?
I am suggesting that the temporary irrigation should be ignored in your calculations. The baseline and design cases should highlight the reduced irrigation needs for the native landscape.
OK. This specific area, of several areas, is being restored with temporary irrigation and would otherwise be spray irrigated and have shrubs and ground cover that need regular water. We have reduced the need for irrigation to a temporary situation. Why would we not then receive credit to our irrigation reduction calculations to achieve the total site irrigation reduction of 50%? It would seem that we are not being credited for eliminating irrigation in this planting area because it doesn't fit in to the calculation spreadsheet. Maybe I am looking at this the wrong way.
Brett, I don't see any reason you shouldn't get credit for it, or any reason it shouldn't be reflected in the calcs. So I think I would need to see whatever you're seeing to understand your predicament. If you want to email me specifics, you can do so at tristan (at) leeduser.com.
The project is a university building remodel. Current landscape will be removed (except for the few mature trees) and replaced after construction. There are currently no shrubs on the site but there will be 1,000 square feet of native scrubs added as part of the project. We are removing parking spaces to do this. Do we enter zero shrubs in baseline calculations and 1,000 sq.ft. in design case? The university has a very efficient irrigation system (Rainbird) which will remain. We are assuming this means it has no effect on either calculation. Help, please!
Since the baseline case is really a theoretical landscape plan using "average values representative of conventional equipment and design practices" (Ref guide pg 121) it doesn't really matter what plantings or irrigation system was there before. I understand the credit is intended to compare your design case to what would "normally" be built, not to what actually was there before. Otherwise, you might be penalized for having a water conserving existing design.
Thus, the baseline irrigation system would not necessarily be an efficient rainbird system, but probably more of a guzzler, so you should be able to take credit for the better system in the design case.
It's left up to the design team's judgement to define what would be "conventional" plantings to list in the baseline case, which might be a combination of turf and other plantings. As for the prior parking spaces being demo'd and planted, this is an odd situation: since the baseline case needs to have the same total planted area as the design case, you probably have to assume those parking areas are also "planted" in the baseline case, which might reasonably be assumed to be turf grass.
Hope that helps!
Our landscape designed a big SOD grass area ( 51,000sqf on a total 8' drop area near our building) with no irrigation system in this project. The WE 1.2 mensioned project can get 2 points in WE1 if no irrigation system. So we should be able to get 2 points, correct? I need talk to our landscape designer. But before that, I am wondering how the big area SOD grass can survive if no irrigation. Will the LEED reviewer question that? Any suggestion?
Yongmei, the credit requirements here are twofold: use native/adapted landscaping, AND use no permanent irrigation. According to the LEED Reference Guide, any monoculture is not considered native/adapted. So whether or not turfgrass can survive without irrigation, it won't meet the credit requirements. You'll need to talk to your landscape designer about a more diverse landscape.
Tristan, thanks for your response. Hmm, the project already built, unfortunately the people who designed landscape for this project didnt pay attention... Now we have to fix it.
Anyway, we did design lots of native trees shrubs near our building. Are you sure that all the landscape have to be native, adapted? we have a project which has some turf grass and no irrigation system, ( but area of turf is not as big as our project) and it got 2 points. Does it depend on the type of turf?
yongmei - while Tristan's intent was correct from an ideal stand point - ie: native planting typically equates to a higher likelihood for compliance for no irrigation needs, the WEc1 does not "require" native/adapted planting. (note: native/adaptive could help with SSc5) With that said, the fact that you have turf grass means you will need to assess, given the rainfall for the site/local climate, whether the grass will survive without water. Aesthetics may come in to play too... we have had clients accept that grass at peak summer/heat may die off/turn brown, and they are ok with this... you may need to explain this to the reviewer, if questioned.
Since the lawn has been installed, and if you (or your client) determine irrigation is now "needed", then the fix can be to install a water efficient irrigation system... and accept only 1 point (or 2 points if you are using 2009). Or you could also add a stormwater collection system sized to irrigate the lawn based on appropriate calculations accounting for annual rainfall. My guess is this is too much added cost and/or site disruption, and you may need to forgo this credit.
Gunnar, thanks for your suggetion. Your guess is right, the client will not add irrigation system/ extra cost for this credit...
I am still wondering we might be able to explain somehow to reviewer because WE 1.2 in the V2.2 version requirement says "install landscaping that is not require permanent irrigation". We do have native trees/ shrubs, and this big SOD grass. If the SOD grass is drought-resistant type, and the client is ok if the grass turn brown at peak summer, then it is a ' landscaping that is not require permanent irrigation, right?
Is there anyone who did get the WE1.2 point with no irrigation on turf grass area?
If you do not have irrigation, you meet the intent of the credit.
We are installing a vegetated roof on the project, and will need to irrigate the roof. We are wondering what should we use as the baseline for the calculation. We want to try and show an improvement in water use, but we aren't sure if this is possible. Any suggestions or previous experience?
Mark, a lot of buildings use non-irrigated plantings for green roofs so the company you are keeping is a bit sparse. Your question is kind of tough to answer because so much depends on site and climate specifics. And then on the site, a roof is often more exposed to drying conditions (wind and direct sun) so the irrigation needs may be higher, but a higher baseline may also be justifiable. I would work with your landscape architect and use everyone's best knowledge and common sense. Tough to give more specific advice than that, at least for now.
If the designer just declare that no irrigation systems are provided by the project and the site plantings have been selected to survive without irrigation once they are established, does not require any documentation including calculation?
No, calculations would not be necessary to document the credit in this situation.
We are repairing an existing irrigation system (replacing heads, modifying layout, etc.) Do I include this in our material cost basis? So far as I can determine we leave out soils and excavation, include plantings and other site improvements. Seems like the irrigation components would be similar to materials used for plumbing and therefor excluded. Impossible to track their manufacturing and resource extraction data.
Do you know what MasterFormat section they fall under? As far as I know, it would be Section 32, and included in the materials budget.
The project was bid and constructed under Masterformat 1995 (Divs 2-16). this was a renovation and the irrigation system serves a larger area outside of the LEED boundary. The modifications that were made to accommodate some site changes were contracted by the Owner and were not bid. We are tracking our material costs as actual construction costs and following MF 2004 divisions. The irrigation repairs fall under 32 80 00. I had assumed that we would include all of the plantings, paving, and other Div 32 items, but exclude soils and excavation along with other Div 31 items.
To conform with the no irrigation (WE 1.2) requirements, is a landscaping and plant specification included in the project manual sufficient for the narrative submittal?
Zarah, I'd suggest a landscape plan, with the legend and a written narrative that explains the design approach and your rational.
Also, please insure that you've met the requirements for WE 1.1. Some folks are missing the fact that TWO strategies are required by 1.1 and getting 1.1 is required to get 1.2
Rick, do you mean that it's a requirement to use at least two things to earn WEc1.1, from the list of Plant species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species., Irrigation efficienc, Use of captured rainwater, etc.? Not sure I was aware of that.
From what we have determined, under 2.2, the "any combination" means that at least TWO of the methods must be utilized. This is a change from prior versions, where plant species alone would get you the credit. If it said "one or more" or "two or more" it would be more clear, but "any combination" is pretty clear in it's intent.
Still, the credit isn't terribly difficult, as we usually always install a high efficiency sprinkler system. However, if this system is only used for establishment (AND is then disabled) , the reviewer many not consider that as a valid claim.
As I read it, the intent is to encourage the use of alternate irrigation in an effort to encourage others to start to shift from potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. to rain water or other alternate sources.
The text of the credit follows:
Reductions shall be attributed to any combination of the following items:
❑ Plant species factorSpecies factor (ks) is a constant used to adjust the evapotranspiration rate to reflect the biological features of a specific plant species.
❑ Irrigation efficiency
❑ Use of captured rainwater
❑ Use of recycled waste water
❑ Use of water treated and conveyed by a public agency specifically for non-potable uses
I actually disagree with your interpretation as requiring at least 2 of the reduction methods, although I am not sure it makes a difference since a combination is the easiest way to achieve a 50% reduction of calculated water budget.
To clarify your other point, you must show a 50% reduction in total water needs before applying non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. sources in order to achieve WEc1.2.
I'm confused - please tell me if I'm reading the above comments correctly: if we are not providing a permanent irrigation system under 1.2, we still need to complete the calculations to earn 1.1? Yet, the template (V2.2) simply lists the 4 options, and under Option #4 (no irrigation), there are no calcs listed. Aside from selecting the option, there isn't anything else to fill out, except describing the documents being uploaded.
So, what else are we supposed to complete for Option #4?
Roxanne, I don't think there is anything else for Option 4. The comments above are for a reduction in irrigation water, which is a different option.
Does that make sense?
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