Sampling Water Fixtures in LEED v4 O+M

Green Building Team on October 28, 2019

Each month we’re highlighting an interesting question you posed to LEED Coach Canada regarding LEED v4/v4.1. LEED Coach Canada is supported by a collaborative team of professionals with diverse technical backgrounds located across Canada. For insightful answers to your LEED questions, email

Question: For the LEED v4 O+M Water Efficiency prerequisite: Indoor Water Use Reduction, is it acceptable to test a sample of water fixtures when manufacturer’s documentation is not available?

Jessica Heiss, LEED Reviewer, answers: If the manufacturer or testing company cannot provide the rated flow rate for fixtures installed within the building, project teams may use on-site tests to report the most accurate volume of water use. This should be done by testing a sample (i.e., 20%) of each installed fixture type at the building’s water pressure. The design case calculations would use the actual measured flow rate of the fixtures installed in the project, and the baseline calculations would use the LEED baseline flow rates included in the LEED v4 Indoor Water Use Reduction Calculator.