Oregon Septic & Well Water Rules

The Oregon Department of Environmental Quality (DEQ) regulates onsite septic systems and licenses installer and pumper businesses.

This is a short state page. It covers only the facts we've verified from official sources so far.

Buying or selling

• DEQ recommends a professional septic evaluation when buying or selling a home.
• Evaluations for property transfer use DEQ's Existing System Evaluation Report (ESER) form under OAR 340-071-0155, done by a qualified evaluator.

Licensed businesses

• Check that an installer or pumper business holds an active license using DEQ's sewage disposal service business license search.

Frequently asked questions

Sources

• Oregon DEQ: Septic Smart
• OAR 340-071-0155
• Oregon DEQ: ESER form (PDF)

Last checked: October 21, 2026