Excavation
Do You Need a Permit for Drainage Work in Oregon?
Cojo
May 30, 2026
6 min read
"Do I need a permit to put in a French drain?" It's one of the first things Oregon property owners ask, and the honest answer is the most frustrating one: it depends. It depends on what you're doing, how much earth you're moving, where the water ends up, and which city or county you're in. There's no single statewide answer, because drainage permitting is mostly local.
This guide lays out the situations that typically do and don't trigger a permit, so you know what questions to ask your jurisdiction. It's general guidance, not a substitute for checking with your local building or public works department. For broader context, see our Oregon drainage guide.
Oregon doesn't have one drainage permit. Cities and counties each set their own rules through building codes, grading ordinances, and stormwater regulations. A French drain that needs no permit in one jurisdiction might trigger a grading permit in another. On top of that, a couple of broader rules — the state DEQ 1200-C stormwater permit and easement law — apply across jurisdictions. So checking with your specific city or county is always step one.
Many small, self-contained drainage projects fall below permit thresholds:
The common thread: small scale, water stays on your property, and you're not altering drainage onto adjacent land or public systems. Our French drain cost in Oregon guide covers these typical residential projects.
But "usually" is doing real work in that sentence. Some jurisdictions require permits for grading above surprisingly low thresholds, so confirm rather than assume.
Permits become likely when the project gets bigger or changes how water moves beyond your property:
One area people overlook: you can't just tie your drainage into a public storm drain because it's convenient. Jurisdictions control connections to their stormwater systems, and an unpermitted connection can mean fines and being ordered to disconnect. If your drainage plan ends at a public storm line or curb, plan on getting the connection permitted.
Even setting permits aside, Oregon water law and common law care about where your drainage discharges. You generally can't collect water and dump it in a concentrated flow onto a neighbor's property. Doing so can create legal liability regardless of whether a permit was involved. This is why a real outfall — your own lower ground, a permitted storm connection, or a lawful destination — matters as much for compliance as it does for function.
The reliable path:
A contractor who works in your area regularly will usually know the local thresholds and connection rules, which is one reason hiring locally pays off on permitting.
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