California just unlocked onsite water reuse. In April 2026 the state finalized uniform regulations to treat and use rainwater (roof runoff), stormwater, greywater (including foundation drainage and condensate) and onsite wastewater in buildings. Help us update the Water Reuse Practice Guide to capture the new rules and design advances since the 2018 edition. Your expertise, resources, or support will accelerate water efficiency locally, regionally, and across the continent.