CS-v4 WEc4: Water metering

  • Submeter at least two water subsystems

    To earn this credit your project must submeterSubmetering is used to determine the proportion of energy or water use within a building attributable to specific end uses such as tenant spaces, or subsystems such as the heating component of an HVAC system. at least two water subsystems. This credit is typically low-cost and easy to implement, while offering significant long-term benefits, including providing building operators with the tools to track, manage, and optimize water use at the subsystem level.

    For the irrigation, indoor plumbing, domestic hot water, 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. subsystems, only 80% of the total end use has to be metered. This provides some flexibility for projects that have design considerations that might prevent metering of 100% of a given subsystem. For boiler metering to contribute to credit compliance, the boiler must use at least 100,000 gallons of water a year, or at least 500,000 BtuH/year. Metering reclaimed water sources can contribute regardless of rate (quantity of water), but 100% of the system must be metered. 

    Several types of meters can meet the credit requirements, from high-end, BAS (building automation system) integrated meters to simple, manual read and clamp-on meters. Note that these submeters need to track consumption within the whole building consumption tracked by the main meter(s) installed per the prerequisite.

    What’s New in LEED v4

    • This is a new credit!

    FAQs

    Are there any requirements for the frequency of meter reading/recording?

    While metering duration and frequency are not specified for this credit, daily and weekly readings provide much higher resolution and better feedback to building operators, compared to monthly and annual tracking. Try to integrate frequent water use reading and analysis into standard operating and maintenance procedures.  

    If a building only has one of the required systems, is it enough to submeter that one or are you not eligible for the credit at all?

    If you have absolutely no other uses, then USGBC's intent is that the project is not eligible for the credit because it's not doing anything beyond what's required in the prerequisite. However, there are often items that can be treated as either domestic hot water or processes. Note that if the water is going to two uses, you can use one whole-building meter and one sub-meter to derive the usage of the second process by subtraction.

  • WE Credit 4: Water metering

    Intent

    To support water management and identify opportunities for additional water savings by tracking water consumption.

    Requirements

    Install permanent water meters for two or more of the following water subsystems, as applicable to the project:

    • Irrigation. Meter water systems serving at least 80% of the irrigated landscaped area. Calculate the percentage of irrigated landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios. served as the total metered irrigated landscape area divided by the total irrigated landscape area. Landscape areas fully covered with xeriscapingXeriscaping is a landscaping method that makes routine irrigation unnecessary. It uses drought-adaptable and low-water plants as well as soil amendments such as compost and mulches to reduce evaporation. or native vegetationAn indigenous species that occurs in a particular region, ecosystem, and habitat without direct or indirect human actions. Native species have evolved to the geography, hydrology, and climate of that region. They also occur in communities; that is, they have evolved together with other species. As a result, these communities provide habitat for a variety of other native wildlife species. Species native to North America are generally recognized as those occurring on the continent prior to European settlement. Also known as native plants. that requires no routine irrigation may be excluded from the calculation.
    • Indoor plumbing fixtures and fittings. Meter water systems serving at least 80% of the indoor fixtures and fitting described in WE Prerequisite Indoor Water Use Reduction, either directly or by deducting all other measured water use from the measured total water consumption of the building and grounds.
    • Domestic hot water. Meter water use of at least 80% of the installed domestic hot water heating capacity (including both tanks and on-demand heaters).
    • Boiler with aggregate projected annual water use of 100,000 gallons (378 500 liters) or more, or boiler of more than 500,000 BtuH (150 kW). A single makeup meter may record flows for multiple boilers.
    • Reclaimed water. Meter reclaimed water, regardless of rate. A reclaimed water system with a makeup water connection must also be metered so that the true reclaimed water component can be determined.
    • Other 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.. Meter at least 80% of expected daily water consumption for process end uses, such as humidification systems, dishwashers, clothes washers, pools, and other subsystems using process water.

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Jun 24 2017
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