Do I have to live on the property to build an ADU?

Oregon removed the statewide owner-occupancy requirement, so in most urban residential cases you don't. Local rules can still vary, so confirm for your specific address.

Can I build an ADU on rural land in Clackamas County?

Since September 2024, ADUs are allowed on many rural residential properties in the county. You'll need to confirm your zoning and plan for septic and well requirements.

How long does ADU permitting take?

It varies with the county's workload and whether a land-use review is needed. Starting the feasibility and permitting early is the best way to keep a project on schedule.

Guide

Clackamas County ADU Regulations, Explained

Oregon's ADU laws opened the door, but permits, setbacks, and county rules still trip up homeowners. Here's a plain-English guide to building a legal ADU in Clackamas County.

Oregon's ADU laws opened the door, but permits, setbacks, and county rules still trip up homeowners. Here's a plain-English guide to building a legal accessory dwelling unit in Clackamas County.

What Oregon law allows

Under House Bill 2001, Oregon requires cities and counties to allow ADUs in urban residential zones that already permit single-family homes, one ADU per single-family lot in most cases. Oregon also removed the old statewide owner-occupancy mandate, so in most urban situations you don't have to live on the property to have an ADU (local specifics can still vary).

Size, setbacks, and design

Size: capped in most cases at 900 square feet
Setbacks: typically 5–10 ft on the sides and 15–25 ft front and rear, though hillside and corner lots vary
Design: detached units must match the primary home's materials, roof shape, and window styles to meet design-compatibility standards

Rural properties (2024 update)

As of September 3, 2024, ADUs became allowed on many rural residential properties in Clackamas County, a meaningful expansion for owners of acreage in areas like Canby and the county's rural fringes. Rural builds also involve septic and well considerations that urban lots don't.

Permits and process

A legal ADU needs building permits, and often a land-use review to confirm the lot qualifies and the unit meets setbacks and size. Because zoning rules vary by district, it's worth verifying your specifics with county Planning and Zoning (503-742-4500), or working with a builder who runs that feasibility check for you before you spend on design.

Frequently asked questions

Do I have to live on the property to build an ADU?: Oregon removed the statewide owner-occupancy requirement, so in most urban residential cases you don't. Local rules can still vary, so confirm for your specific address.
Can I build an ADU on rural land in Clackamas County?: Since September 2024, ADUs are allowed on many rural residential properties in the county. You'll need to confirm your zoning and plan for septic and well requirements.
How long does ADU permitting take?: It varies with the county's workload and whether a land-use review is needed. Starting the feasibility and permitting early is the best way to keep a project on schedule.