Do You Need a Permit for Drainage Work in Oregon?

The Question Everyone Asks (and Most Get Wrong)

"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.

Why It's Local

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.

Work That Usually Doesn't Need a Permit

Many small, self-contained drainage projects fall below permit thresholds:

• A modest French drain or yard drain that stays on your property and discharges to your own land
• Extending a downspout or adding a pop-up emitter
• A small area drain for a patio puddle
• Minor grading that moves a small volume of soil and doesn't change where water flows onto neighbors

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.

Work That Often Does Need a Permit

Permits become likely when the project gets bigger or changes how water moves beyond your property:

• Significant grading — moving a substantial volume of soil, often measured in cubic yards or by the area disturbed. Most jurisdictions set a grading-permit threshold.
• Disturbing an acre or more — this triggers the state's DEQ 1200-C construction stormwater permit on top of local rules. See our DEQ 1200-C stormwater permit guide.
• Connecting to a public storm system — tying a drain into a city storm drain or curb almost always requires permission and a connection permit.
• Changing where water flows onto a neighbor — redirecting concentrated runoff onto adjacent property can trigger review and create liability.
• Work in or near a sensitive area — wetlands, streams, floodplains, and steep slopes carry their own rules and setbacks.
• Work within a recorded drainage easement — easements come with restrictions on what you can build or alter. Our drainage easements explained guide covers them.

The Stormwater Connection Rule

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.

The "Where Does the Water Go" Question

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.

How to Find Out for Your Project

The reliable path:

1. Call your city or county building or public works department and describe the project — size, what you're moving, where water ends up.
2. Ask specifically about grading permits, drainage permits, and stormwater connection permits.
3. Check whether the site is in or near a sensitive area or a recorded easement.
4. Confirm the DEQ 1200-C threshold if you're disturbing close to an acre.

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.