LEED 2012 – 2nd Public Comment – Water Efficiency (WE) Section
Key changes in the the Water Efficiency (WE) section of LEED-NC (part of LEED BD&C) in the second public comment draft of LEED 2012 are discussed below. Do you have comments or questions on this draft? Discuss them below with your fellow LEED professionals. Substantive comments posted here during USGBC's second public comment period will be submitted to USGBC and considered "official" public comments.
Water Efficiency (WE)
The Landscape Water Use Reduction prerequisite introduced with the first draft now has a simpler compliance path, in which projects show that the landscaped area does not need irrigation. All other projects with over 1,000 ft2 of exterior vegetated space would still need to reduce water use for the peak watering month 30% below a baseline established by the WaterSense Water Budget Tool.
The 20% water reduction baseline required by Minimum Fitting and Fixture Water Use Reduction is unchanged from the LEED 2009 water use reduction prerequisite. There are some minor changes to this draft, but the most interesting is a change in scope: only fixtures within the project scope would fall under the prerequisite here, not all fixtures in the building.
The Appliance and Process WaterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making. Use Reduction prerequisite, new in the first draft, sets minimum performance requirements for some appliances and processes. As with the fixture prerequisite, this one also contains a change limiting it to the project scope. Energy Star ice machines have been added to the requirements, and they must also use air-cooled or closed-loop cooling.
The wording of Additional Fixture and Fitting Water Use Reduction (2–4 points) is simplified, with the language now referring to the prerequisite. The big change is that the proposed point thresholds are more stringent: 35% reduction for 1 point, but 40% reduction for 2 points, and 50% for three.
Tweaks to Sustainable Wastewater Management (1–2 points; previously “Innovative Wastewater Technologies”) appear to make this credit more achievable, while also offering a higher bar. Reducing sewage conveyance by 50% through Option 1 would earn one point, but reducing it by 95% would earn two points. In Option 2, reuse of 95% of wastewater would earn two points, but implementation of wastewater reuse at any level (no lower limit is given) would earn one point. Under Option 3, one point could be earned for implementing (no threshold is given) resource recovery for key wastewater nutrients (nitrogen and phosphorous), while two points would be earned for also addressing recovery of organic carbon.
Additional Landscape Water Use Reduction (1–2 points) is similar to the prerequisite (see above) in its use of the WaterSense Water Budget Tool. Fairly minor changes have been made to requirements and calculations, and the credit thresholds (50% and 100%) remain unchanged from LEED 2009. Playgrounds and athletic fields may be excluded from the credit calculations, but other best management practices such as metering must be in place for those areas.
In Cooling Tower Makeup Water (1–2 points) there have been some wording and reorganizing that does not appear to amount to significant changes to this credit, which would be new for LEED-NC projects.
Revisions to the new Additional Appliance and Process Water Use Reduction credit (1 point) since the first LEED 2012 draft create a menu of choices. Commercial washing machines, commercial kitchen equipment, commercial laboratory and medical equipment, commercial vehicle washing systems, and municipal steam systems all fall under this credit. Earning it means establishing eligibility for a given category (being connected to a municipal steam system, for example), and then meeting specified requirements for all of the given equipment within the project scope. In most cases, that entails meeting efficiency standards; in the case of municipal steam, projects would recover and reuse steam condensate.
What do you think of the proposed changes? Post your comments or questions below.