Fees
Estimated city fees
Baseline for a simple permitted adu: Portland BDS permit and plan review fees are valuation-based. A new detached ADU valued at $150,000–$250,000 commonly generates $2,000–$5,000+ in combined permit and plan review fees before SDC waiver. Verify with Portland BDS.
| Fee | Amount | Notes |
|---|---|---|
| Building permit fee | Valuation-based | Portland BDS charges building permit fees based on declared construction valuation. Use the Portland BDS permit fee schedule at portland.gov/bds for current amounts. |
| Plan review fee | Valuation-based | A plan review fee is charged separately from the building permit fee. Portland BDS calculates this based on project valuation and type. |
| System Development Charges (SDCs) | Potentially waived for qualifying ADUs | Portland offers an ADU SDC Waiver program. SDCs can otherwise be significant for new dwelling units. Confirm current waiver availability and eligibility with Portland BDS at application. |
| Oregon Building Codes Division surcharge | 1% of permit fee | A state surcharge of 1% of the permit fee is collected by Portland and remitted to the Oregon Building Codes Division on residential permits. |
| Utility connection fees | Project-specific | A separate water, sewer, or utility connection for the ADU may trigger Portland Water Bureau or Bureau of Environmental Services fees. |
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Conditions
The rules that apply
- A building permit is required for any Accessory Dwelling Unit (ADU) in Portland, whether attached (internal conversion or addition) or detached.
- Portland regulates ADUs under Title 33 (Planning and Zoning Code), Chapter 33.205. ADUs are allowed in single-dwelling residential zones (R1, R2, R2.5, R3, R5, R7, R10, R20) as well as multi-dwelling residential zones that allow single-family homes.
- Oregon HB 2001 (signed 2019) requires cities with more than 10,000 residents to allow ADUs by right in all areas where single-family homes are permitted, prohibiting certain local barriers.
- Portland allows one ADU per lot on lots with a single primary dwelling. The ADU may be attached (within or added to the primary structure) or detached.
- Maximum ADU size in Portland: 800 square feet of living area, or 75% of the living area of the primary dwelling, whichever is less. Garages and storage areas do not count toward the size limit.
- Portland eliminated its owner-occupancy requirement for ADUs in 2018, prior to Oregon HB 2001. The property owner is not required to live on site.
- No additional off-street parking is required for a new ADU in Portland. Portland removed its ADU parking requirement.
- Portland waived System Development Charges (SDCs) for ADUs through its ADU SDC Waiver Program. Verify current waiver availability with Portland Bureau of Development Services before applying.
Documents
What you'll need to file
- Completed building permit application submitted through Portland's Development Hub (ePlans).
- Site plan showing lot dimensions, existing dwelling, proposed ADU footprint, setbacks, impervious surfaces, and utility lines.
- Architectural plans including floor plans, elevations, cross sections, and roof plan.
- Structural plans or engineering calculations for elements beyond prescriptive code.
- Oregon Energy Efficiency Specialty Code (OEESC) compliance documentation.
- Stormwater management plan if the project adds impervious surface above Portland's threshold.
- SDC Waiver application if claiming the ADU System Development Charge waiver.
- Contractor's Oregon Construction Contractors Board (CCB) license number if a contractor is performing permitted work.
Process
How the permit process works
Sequential — each step gates the next.
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Confirm zoning and lot eligibility Use Portland Maps (portlandmaps.com) to verify the parcel zone. ADUs are allowed by right in all single-dwelling and applicable multi-dwelling residential zones under Title 33.205 and Oregon HB 2001.
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Determine ADU type and design parameters Decide between an attached ADU (conversion or addition to the primary structure) or a detached ADU (separate structure). Confirm the proposed size is within Portland's 800 sqft or 75%-of-primary-unit limit and meets setback standards.
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Prepare permit package Assemble site plan, architectural drawings, structural documents, energy code compliance, and any stormwater materials. Portland BDS provides guidance documents and pre-application resources on its ADU page.
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Apply for SDC waiver (if applicable) If claiming the ADU System Development Charge waiver, submit the SDC Waiver application to Portland BDS alongside or before the building permit application. Confirm current waiver availability.
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Submit through Portland Development Hub (ePlans) File the building permit application and upload plans through Portland's online permit portal. Pay the plan review deposit at intake.
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Respond to plan review corrections Portland BDS reviewers will issue correction notices if the plans need changes for zoning, structural, energy, or stormwater compliance. Address each correction promptly to advance the application.
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Pay remaining fees and issue the permit After plan approval, pay the remaining permit fees. Portland BDS issues the permit; post it at the job site before construction begins.
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Complete inspections and obtain occupancy Schedule required inspections (footing, framing, insulation, mechanical, final) through Portland's permit portal. Once all inspections pass, Portland BDS finalizes the permit and the unit may be occupied.
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Tools & materials
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Provenance
Code basis & official sources
Last verified 2026-04-18.
Portland City Code Title 33 Chapter 33.205 (Accessory Dwelling Units), Oregon Residential Specialty Code (ORSC), Oregon Energy Efficiency Specialty Code (OEESC), and Oregon HB 2001 (2019) middle-housing mandate.
Residential permit page: https://www.portland.gov/bds/building/accessory-dwelling-units-adus
If you skip the permit
- Portland BDS can issue a Stop Work Order and require full after-the-fact permitting for any unpermitted ADU construction.
- An unpermitted ADU cannot be lawfully occupied or rented; it lacks a Certificate of Occupancy.
- After-the-fact permitting is more costly and may require opening finished walls or correcting non-compliant work before inspections can pass.
- Code enforcement complaints can result in daily fines and liens under Portland City Code.
- Title and financing complications arise when a property with an unpermitted dwelling unit is sold or refinanced.
- Oregon CCB law requires a licensed contractor for permitted work done by a contractor; use of an unlicensed contractor creates additional legal exposure.
FAQ
Common Portland adu permit questions
Do I need a permit for an ADU in Portland, OR?
Yes. Any ADU — attached or detached — requires a residential building permit from Portland BDS. Portland's ADU rules under Title 33.205 treat the ADU as a separate dwelling unit, not as a simple accessory structure.
What is the maximum ADU size in Portland?
The Portland ADU size limit is 800 square feet of living area or 75% of the living area of the primary dwelling, whichever is less. Garage and storage spaces are not counted toward this limit.
Does Portland require the owner to live on site for an ADU?
No. Portland removed its owner-occupancy requirement for ADUs in 2018. Oregon HB 2001 (2019) also prohibits cities from using owner-occupancy as a condition of ADU approval.
What are the System Development Charges (SDCs) for an ADU in Portland?
Portland offers an ADU SDC Waiver program that can eliminate or reduce SDCs, which can otherwise amount to tens of thousands of dollars for a new dwelling unit. Verify current waiver availability and eligibility with Portland BDS before applying.
Does Portland require parking for an ADU?
No. Portland does not require additional off-street parking for an ADU. This was removed prior to the Oregon statewide mandate.
How long does an ADU permit take in Portland?
Standard plan review at Portland BDS typically takes 4–8 weeks. Total time from submittal to permit issuance is often 8–20 weeks. Correction rounds and SDC waiver processing can extend the timeline.
What does Oregon HB 2001 mean for Portland ADU owners?
HB 2001 (2019) requires all Oregon cities over 10,000 residents to allow ADUs by right in all areas that allow single-family housing, and prohibits owner-occupancy mandates and certain other local barriers. Portland was already ahead of most HB 2001 requirements before the law passed.
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Disclaimer: Informational only — not legal advice. Rules change; verify with Portland permitting staff before you build.