Oregon Well Water Testing Requirements
Oregon Revised Statute 448.271 — the Oregon Domestic Well Act — requires water quality testing when selling a home on a private well. Here is what buyers, sellers, and real estate agents need to know.
6 min read · Waterlab Corp Laboratory Staff
Real estate transaction? Call us early.
📞 Call Waterlab Corp at 503-363-0473 as soon as you list (or while preparing the home for sale)
✓ Realize the water testing MAY not pass. Particularly if it has been a long time since the last testing.
⏱️ Samples need 3rd party collection — testing takes up to 14 business days
⚠️ If treatment is needed, add more time to your timeline
Who must comply
Property sellers must provide test results to buyers and Oregon Health Authority. This rule does not apply to any home sales where a spring is the water source. This requirement applies to single-family homes, manufactured homes on private wells, and any property where the well is the primary water source.
Which tests are required
Oregon law requires testing for Total Coliform Bacteria, Nitrate-Nitrogen, and Arsenic at minimum. Lenders (FHA, VA, USDA) may require additional tests — always confirm with your lender early in the transaction.
The lab must be ORELAP-accredited
Results are only valid under ORS 448.271 if they come from a laboratory accredited by the Oregon Environmental Laboratory Accreditation Program (ORELAP). Waterlab Corp holds ORELAP accreditation #100039. Home test kits from hardware stores do not qualify.
Timing and validity
The test must be conducted within 12 months prior to closing. Oregon does not specify how long a sample result is valid for samples ahead of a sale, but best practice is to test as early in the transaction as possible so there is time to address any problems before closing.
What if results show contamination
Oregon requires test results to be disclosed to the buyer — the state is gathering data, not enforcing drinking water standards for private wells. Options include treatment system installation, re-testing after treatment, price negotiation, or well remediation. Waterlab Corp staff can advise on follow-up sampling protocols.
Seller vs. buyer responsibilities
Oregon law places the testing obligation on the seller. However, buyers often request additional tests beyond the legal minimum. Buyers should request the test results early and review them with their agent and, if results are borderline, with a water quality professional.
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