Gray water, or greywater, is wastewater that is generated from a variety of sources in homes and commercial buildings through the use of water for showers, washing machines, bathroom sinks, dishwashers, or other uses. Greywater does not contain serious contaminants and does not include water from toilets or urinals. The Department of Health (DOH) is responsible for developing standards, procedures, and guidelines, with input from technical experts, for the cost-effective reuse of greywater.
Nonpotable water is water that is not of drinking quality, but may still be used for many other purposes, depending on its quality. Nonpotable water is generally all raw water that is untreated such as from lakes, rivers, groundwater, natural springs, and ground wells. Nonpotable water sources also include rainwater, reclaimed/recycled water, and greywater. While nonpotable water is not appropriate for human consumption, it can be used in a myriad of other applications, such as doing laundry and toilet flushing.
On-site nonpotable water reuse systems capture and treat water sources generated from within or surrounding a building, such as wastewater, greywater, stormwater, or roof collected rainwater. The treated water is then reused onsite or locally for nondrinking purposes.
The Department of Health (DOH) is required, in consultation with the Washington State Building Code Council (SBCC) and the Washington State Association of Plumbers and Pipefitters, to adopt rules by July 1, 2022 for:
At minimum, the adopted rules must address:
The rules take effect December 31, 2022. However, if any on-site treated nonpotable water systems are in operation before January 1, 2022, then such systems must be in compliance with the rules by January 1, 2024.
The permitting local jurisdiction may grant a permittee a waiver of compliance with the rules if the local jurisdiction finds that the permittee is unable to come into compliance with the rules because the engineering, repair, or replacement of the system is cost prohibitive.
The DOH may consult or contract with other public or private entities, including the SBCC and the Department of Ecology, for advice on state building code language, water rights, water quality, and other technical matters relating to adoption of the risk-based water quality standards.