Leadership in Energy and Environmental Design (LEED) Changed LEED-Green-Associate Questions

Graywater includes wastewater from lavatory faucets, whereas blackwater includes wastewater from toilets and urinals. This describes the difference between graywater and blackwater according to LEED. Graywater is wastewater that has been used for non-potable purposes, such as washing hands or dishes, but does not contain human or animal waste. Blackwater is wastewater that has been contaminated with human or animal waste from toilets or urinals. Graywater can be reused for certain purposes after minimal treatment, such as irrigation or toilet flushing, whereas blackwater requires more advanced treatment before reuse or disposal. The LEED Green Associate Candidate Handbook states that one of the strategies for achieving water efficiency is to “use non-potable water (graywater) for sewage conveyance” [1, p. 14]. References: LEED Green Associate Candidate Handbook, [Graywater vs Blackwater | U.S. Environmental Protection Agency]

The LEED minimum program requirements state that for LEED BD+C and LEED O+M rating systems, the LEED project must include a minimum of 1000 ft2 (93 m2) of gross floor area1.

LEED v4: Building Design + Construction Guide

LEED minimum program requirements

LEED For Building Design And Construction (LEED BD+C) Rating Systems In Details

Submetering systems are the correct answer because they allow facility operators to measure water use by system, area, or end use. LEED Water Efficiency emphasizes not only reducing water demand but also tracking performance over time. Submeters help identify leaks, unusual consumption patterns, inefficient irrigation, cooling tower issues, process water use, or fixture problems. Occupant schedules and building operating times may help estimate water use, but they do not provide direct consumption data. Fixture cut sheets are useful during design and documentation because they show fixture performance, but they do not help operators optimize actual ongoing water use unless paired with measurement. Submetering supports continuous improvement, accountability, troubleshooting, and better management of potable and non-potable water resources.