Rainwater laws / Washington
Is it legal to collect rainwater in Washington?
Checked at Washington's own statutes and agencies, November 2026. Not legal advice.
Allowed, with limits
Yes, without a water right permit, as long as the rainwater is used on the property where it's collected.
What the rules say
- Ecology policy POL-1017: "the on-site storage and/or beneficial use of rooftop or guzzler collected rainwater is not subject to the permit process."
- "Rainwater must be used on the property where it is collected." For drinking water, check with your county.
Before you buy a big tank
State law is only one layer. Cities and counties can set their own rules, especially for tanks plumbed into the house, and an HOA can limit where a barrel sits. Drinking rainwater needs treatment everywhere. For a barrel or two on a downspout for the garden, the state rule above is usually the one that matters.
Where the numbers come from
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