Tap water and supplyTool

Water map: your supplier, watershed and groundwater

By The Downspout · Updated Oct 11, 2026 · 1 min read Share

Enter an address or click the map. We show who supplies your water, which watershed you live in, and which groundwater basin is under you.

How to read it

• Supplier. A city, district or company that sells you water. If none shows, you may be on a private well.
• Watershed. The land that drains to the same creek. Rain on your roof and runoff from your yard go to the subwatershed first, then the Russian River or another larger system.
• Groundwater basin. A mapped layer of sand, gravel and soil that holds water. It matters most if you have a well. Wells in hills and mountains often draw from rock, which this map does not cover.

Next: test your well or see where tap water comes from.

Address search uses OpenStreetMap, so a new street may not be found. Click the map as a backup. Boundaries are public data and can be off at the edges. Do not use this map to prove where a property line or a service area ends.

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