The U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) and the Green Globes program are two nationwide programs that offer certification of non-residential structures based on their environmental performance, including their use of water. While LEED and Green Globes cover similar topic areas and outline similar standards, these systems do vary both in the specific topics they cover, and the performance criteria and point systems they use. The LEED rating system covers several green building topic areas, and several types of non-residential buildings as well as residences, neighborhoods, and both new construction and existing buildings. For the purposes of this summary, two of the major LEED certification standards for non-residential structures are summarized here-LEED for New Construction (NC), and LEED for Existing Buildings (NB). It should be noted that LEED water performance standards for Core/Shell (CS) are the same as those for NC.
Water and Green Building Certifications
|Water Use Component||LEED NC||LEED EB||Green Globes|
|Fixtures (faucets, toilets, showers)||Uses 1992 Energy Policy Act fixture standards as a baseline. Use 20 percent less water than baseline, or 30 percent for higher score.||Reduce fixture potable water use to baseline or lower. Baseline is 120 percent of water use if all fixtures outfitted with 1992 Energy Policy Act fixture performance requirements. At least one building meter required.||Uses 1992 Energy Policy Act fixture standards as a minimum benchmark. Points awarded for water efficiency above baseline. Highest score for efficiency 30 percent or more above baseline.|
|Irrigation||Reduce potable water by 50 percent from mid-summer baseline through plant selection, irrigation efficiency, use of captured rainwater or recycled wastewater, or non potable water.
Higher points awarded for avoiding use of potable water or using landscaping that does not require irrigation.
|Reduce potable water use 50 to 95 percent through improved irrigation technologies, use of non-potable water, or changes in landscaping.||Minimize use of potable water for irrigation or avoid irrigation altogether. Where potable water is used, employ low volume sprinklers, drip irrigation, programmable controllers, and moisture sensors.
Highest points awarded for landscapes that avoid the needs for irrigation altogether and avoid lawns.
|Sewage Conveyance||Reduce potable water use for sewage conveyance through water conserving features or non potable water for plumbing.
Alternately, treat 50 percent of wastewater on-site to tertiary standards and use onsite treatment or infiltration.
|Reduce potable water use for building sewage conveyance by 50 percent, or treat 100 percent of wastewater onsite to tertiary standards.||For wastewater, points are awarded for greywater or blackwater collection, treatment, and distribution system; and for composting toilets.|
|Other||For discharge water, comply with National Pollutant Discharge Elimination System (NPDES) permit if required.||Use of water for cooling towers should employ automatic controls, conductivity probes, automated blowdown systems, delimiters, and/or water data loggers. Points added for each sub-meter added for high water use operations (irrigation, commercial kitchens, boilers, etc.)|
East Bay Municipal Utility District has instituted progressive water efficiency requirements that may also be informative for new construction.