Background: Potable water is water of a quality suitable for drinking, cooking, and personal bathing. Nonpotable water is water that is not safe for human consumption, but may still be used for 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, and also includes rainwater, reclaimed or recycled water, and greywater.

Greywater or gray water is the term used to describe water segregated from a domestic wastewater collection system and reused on-site. This water can come from a variety of sources such as bathtubs, showers, bathroom sinks, washing machines, dishwashers, and kitchen or utility sinks. It contains some soap and detergent, but is clean enough for nonpotable uses. Greywater does not include flows from a toilet or urinal. Reclaimed or recycled water is domestic wastewater (sewage) from residences and businesses that has been treated at a wastewater treatment plant, that is separated, further treated and cleaned, and tested to ensure it is safe for use.

DOH and the Department of Ecology (Ecology) are required to develop standards for reclaimed water use and to jointly administer a reclaimed water program. Reclaimed or recycled domestic wastewater is treated and tested so that it is safe for use. Reclaimed water may be used for watering grass and plants and to flush toilets in commercial and industrial facilities, as well as replenishing groundwater supplies and increase instream flows of rivers and streams. This water is delivered through purple pipes indicating that it is not intended for drinking water purposes.

Onsite non-potable water reuse systems (ONWS) 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 non-drinking purposes, such as toilet flushing, clothes washing, and ornamental plant irrigation.

Summary of Bill: The Department of Health (DOH), in consultation with the Washington State Building Code Council (SBCC), must adopt rules by July 1, 2021 to take effect December 31, 2021 for:

risk-based water quality standards for treating and reusing on-site nonpotable alternative water sources for nonpotable end uses in multifamily residential, commercial, and mixed-use buildings, and in district-scale projects, including a mix of multifamily residential, commercial, and mixed-use buildings; and
construction standards for adopting the risk-based framework water quality standards.

The rules must address:

risk-based log reduction targets for the removal of pathogens for alternative water sources, including wastewater from all domestic fixtures, gray water, rainwater, and stormwater for nonpotable end uses such as toilet and urinal supply water, clothes washing, irrigation, and dust suppression;
treatment and performance requirements;
water quality monitoring requirements;
reporting requirements for the treatment, performance, and water quality monitoring results;
notification and public information requirements;
cross-connection controls; and
permitting.

Waste water from domestic fixtures may not be used for irrigation of land where food products are or could be produced.

On-site treated nonpotable water systems in operation before January 1, 2021 must be in compliance with the rules by January 1, 2023. If a local jurisdiction finds a permittee is working to comply with the rules, but due to extenuating circumstances related to the engineering, repair, or replacement of the system an extension is warranted, the local jurisdiction may grant an extension. However, the extension may not exceed January 1, 2025.

DOH may consult or contract with other public or private entities, including, but not limited to, SBCC and 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.