# Washington — Private well water testing at property sale: which states require it

For Washington, testing required at sale? is In most counties when you buy or sell a home with a private well, the county health or planning department, or the lending institution involved, may require the seller to provide water-sampling results to show the water is safe to drink; who tests / pays is the seller, verified against its source on 2026-08-19.

- **State:** Washington _(our reading, not quoted from the source)_
- **Testing required at sale?:** In most counties when you buy or sell a home with a private well, the county health or planning department, or the lending institution involved, may require the seller to provide water-sampling results to show the water is safe to drink _(verified: appears in the quote below)_
- **Who tests / pays:** the seller _(verified: appears in the quote below)_

## What the source says

> If you own a private well, you are responsible for testing your own water. In most counties when you buy or sell a home with a private well, the county health or planning department, or the lending institution involved, may require the seller to provide water-sampling results to show the water is safe to drink. Contact your local county health or planning department for information on the requirements and the testing needed.

## Source

- https://doh.wa.gov/community-and-environment/drinking-water/contaminants/testing-your-water

Last verified: 2026-08-19. Review by: 2027-08-19.
Part of [Private well water testing at property sale: which states require it](https://referencesource.org/well-water-testing-at-property-transfer/).