As part of LEED for Homes Water Efficiency credit 1, the project utilizes two 1500 gallon cisterns. The cisterns are made of concrete and will be buried below the auto-court between the residence and ADU. Water is collected from 100% of the roof area on the two buildings and will be used throughout the site. The Washington State Department of Ecology has several restrictions on how much water can be collected on residential sites. In this case the project benefited greatly due to its proximity to the Puget Sound and is exempt from many of the restrictions. The cisterns will only supply water for exterior use. The state does not currently differentiate between grey and black water which in turn restricts the use of rainwater for flushing toilets and the like. The State of Washington has legislation in progress that would allow the future use of grey-water in the interior of residences. Let’s hope this passes so that we can really begin to reduce our water consumption!