Portland has become one of the most ADU-friendly cities in the country. If you have been thinking about adding a backyard cottage, converting your garage, or building an attached unit for a family member, the Portland ADU rules for 2026 give you more flexibility than almost anywhere in Oregon. But flexibility does not mean simple. Setbacks, lot coverage limits, permit steps, and the SDC waiver program all have specific requirements that determine whether your project goes smoothly or stalls before it starts.
This guide covers everything Portland homeowners need to know before breaking ground: what you can build, where you can build it, how the permit process works at the Bureau of Development Services, and how to qualify for the SDC waiver that can save you significant money in infrastructure fees.
Whether you are planning an ADU for rental income, a multigenerational family, or to house an aging parent in a fully accessible space close to home, these are the rules that apply to your project right now.
Owner-occupancy is no longer required. Portland eliminated that requirement in 2020, meaning you can build and rent an ADU even if you do not live on the property. The SDC waiver still has its own eligibility requirements, which we cover in full below.
What Is an ADU and What Types Does Portland Allow?
An accessory dwelling unit is a self-contained residential unit on the same lot as a primary residence. It must include independent living facilities: its own kitchen or kitchenette, sleeping area, and bathroom. Portland’s zoning code recognizes several distinct types.
Detached ADUs are standalone structures separate from the primary home. These are often backyard cottages built from the ground up on the rear portion of the lot. They are the most common type for families creating independent living space for an aging parent or adult child.
Attached ADUs share a wall with the primary residence and are built as an addition to the home. They often share the main structure’s foundation and roofline while maintaining fully separate living facilities.
Internal ADUs are carved out of existing space within the primary home, such as a basement apartment or a converted upper floor. Because they add no new footprint, they often have simpler structural requirements.
Garage conversions repurpose an existing attached or detached garage into habitable living space. Portland sees a large volume of these projects because existing structures reduce the scope of construction significantly.
Suite Additions builds all four types across the Portland metro area, from custom backyard cottages in Portland to garage conversions in Tigard and Beaverton. The ADU service page covers the full scope of what we design and build.
Portland ADU Size Limits: How Big Can You Build?
Size is one of the most frequently misunderstood aspects of Portland ADU rules. Here is the accurate picture for 2026.
A detached ADU can be up to 800 square feet of floor area by right. This is the standard limit that applies in most residential zones without requiring any special review. A detached ADU can also be up to 75 percent of the primary dwelling’s floor area, whichever calculation produces the smaller number for your specific property.
For attached ADUs, the same 800 square foot limit applies in standard cases. The attached unit must be clearly subordinate to the primary residence and cannot exceed the primary dwelling’s footprint in most configurations.
ADUs larger than 800 square feet may still be possible on some properties under Portland’s middle housing rules introduced through Oregon House Bill 2001, which allows up to four total units on single-family lots. However, these larger configurations involve additional review steps and may trigger SDC charges that the standard waiver program does not fully cover.
Height limits for detached ADUs typically range from 20 to 25 feet, roughly matching the scale of the primary home. Check PortlandMaps for your specific zone’s height allowance before finalizing a design.
Portland ADU Setback Requirements: How Close to the Property Line Can You Build?
Setbacks define how close your ADU can sit to your property boundaries. Getting these wrong during the design phase is one of the most common reasons Portland ADU permit applications need revision.
For detached ADUs, Portland Zoning Code 33.205.040.D establishes a minimum 5-foot setback from both side and rear property lines. This is the baseline requirement in standard residential zones. Some zones require larger setbacks, so confirming your specific zone’s requirements through PortlandMaps or a pre-application conference with BDS before investing in full drawings is strongly recommended.
Existing structures like garages converted to ADUs may be permitted to maintain their current setback position even if it is less than 5 feet, provided the structure already exists and the conversion does not increase its footprint toward the property line.
The front setback rules are generally more restrictive. Detached ADUs are typically required to be sited toward the rear of the lot, not at the street frontage. This preserves the primary residence’s relationship to the street and keeps the ADU character subordinate.
Lot coverage is the companion rule to setbacks. The total footprint of all structures on your lot, including the primary home, the ADU, and any covered structures, must not exceed the zone’s lot coverage maximum. In most Portland residential zones, this maximum is 50 percent of the lot area. An ADU that satisfies the setback rules but pushes total coverage over the limit still cannot be built as designed.
Portland ADU Rules at a Glance: Detached vs Attached Comparison
Use this table as a quick reference before your first design meeting or contractor conversation.
| Rule | Detached ADU | Attached / Garage Conversion |
| Max Size | Up to 800 sq ft (by-right) | Up to 75% of primary unit or 800 sq ft |
| Rear Setback | 5 feet minimum | 5 feet minimum (existing garages may vary) |
| Side Setback | 5 feet minimum (zone-dependent) | 5 feet minimum (zone-dependent) |
| Height Limit | Typically 20 to 25 feet | Generally matches primary structure |
| Lot Coverage | Counts toward zone max (usually 50%) | Counts toward zone max (usually 50%) |
| Parking Required | No | No |
| Owner-Occupancy | Not required since 2020 | Not required since 2020 |
| SDC Waiver Eligible | Yes, with 10-year covenant | Yes, with 10-year covenant |
| Permit Path | Ministerial (by-right), 4 to 8 weeks | Ministerial (by-right), 4 to 8 weeks |
Planning an ADU in Portland? Suite Additions handles permits, design, and construction from start to finish. Schedule a free consultation today.
How Does the Portland ADU Permit Process Work in 2026?
Portland processes most ADU permits through a ministerial, by-right review at the Bureau of Development Services. This means that if your project meets all the code requirements, it is approved without a discretionary land use hearing. That is a significant advantage compared to many other cities where neighbors can object to or block an ADU during a public review process.
Here is the standard permit path for a straightforward detached ADU:
- Verify a lot of feasibility. Before spending money on drawings, confirm your lot’s zone, setbacks, lot coverage limit, and any special overlays through PortlandMaps. Check for tree canopy, historic district status, or landslide hazard overlays that could complicate or lengthen review.
- Pre-application conference (optional but valuable). BDS offers a paid pre-application conference where staff review your site-specific situation before you submit drawings. Projects that skip this step sometimes discover site-specific issues during plan review that require design changes and resubmission.
- Prepare and submit permit documents. Your submittal package needs site plans showing property boundaries, existing structures, and the proposed ADU footprint with all setback dimensions labeled. Floor plans, elevations, and energy compliance documentation are also required. Incomplete submittals are the leading cause of review delays.
- Apply for the SDC waiver simultaneously. If you intend to use the SDC waiver program, the covenant application must be submitted alongside your building permit application. It cannot be added after the permit is issued.
- Plan review. Standard ADU permits move through plan review in four to eight weeks for complete submittals. Projects with tree removal, historic review, or complex utility situations can take four to six months. Check BDS’s current posted wait times before setting your construction schedule.
- Inspections and final approval. Construction inspections are required at framing, insulation, and mechanical stages. A final inspection and certificate of occupancy close out the permit.
Suite Additions manages the complete permitting process for every ADU project we build across Tualatin, Hillsboro, and the wider Portland area. You do not have to navigate BDS on your own.
The Portland ADU SDC Waiver: What It Is, Who Qualifies, and How to Apply
This is the most important section of this guide for most Portland homeowners. The System Development Charge waiver can eliminate thousands of dollars in infrastructure fees that would otherwise be charged when a new dwelling unit is created on your property.
What Are SDCs?
System Development Charges are one-time fees assessed by multiple Portland bureaus when a new unit is created. They represent your project’s proportional share of the public infrastructure that the new unit will use: water, sewer, stormwater, transportation, and parks. For a standard detached ADU in Portland, these charges have been reported in the range of tens of thousands of dollars depending on the specific bureaus and their current fee schedules.
Request a project-specific SDC calculation from BDS for your actual lot before using any published estimate as a planning number. The bureaus update their fee schedules annually, and the difference between published estimates and your actual charge can be significant.
What Does the SDC Waiver Cover?
Portland’s SDC Waiver Program, established under Portland City Code 17.14.070, provides a full waiver of every applicable system development charge for eligible ADUs. This is not a partial reduction. It is a complete elimination of SDC fees for qualifying projects, making it one of the most financially meaningful decisions you will make during the planning phase.
Who Qualifies for the SDC Waiver?
To qualify for the Portland ADU SDC waiver in 2026, your project must meet these requirements set by the City’s Revenue Division:
- Long-term residential use only. The ADU must be owner-occupied or rented on a month-to-month basis or longer. It cannot be used as a short-term rental such as Airbnb or VRBO for the full 10-year covenant period.
- 10-year covenant agreement. You must sign and record a binding covenant with the City of Portland committing to these use restrictions. The covenant is recorded against the property title and binds all owners during its term, not just the current owner.
The covenant means that neither the ADU nor the primary residence can be rented as a short-term rental for 10 years. If you plan to use either unit for Airbnb or VRBO, the SDC waiver is not available to you.
Important 2026 Update: SDC Waiver Sunset Status
Portland BDS proposed sunsetting the SDC waiver program entirely. After significant pushback from the Home Builders Association of Metro Portland and industry stakeholders, the city tabled the immediate sunset and kept the program running while broader discussions continue. As of this guide’s last update, the waiver is still active.
If your planning depends on the SDC waiver, confirm its current status directly with the Revenue Division before finalizing your budget. The program’s future remains a live policy question and the status could change during a multi-month project timeline.
How to Apply for the SDC Waiver
The application is submitted directly to Portland’s Revenue Division by email at aducovenant@portlandoregon.gov with your permit number in the subject line. The Revenue Division reports a 99 percent approval rate for applications that follow the instructions correctly. Incomplete or incorrect applications cause delays. Download the current application packet from Portland.gov before filling it out.
| Pro Tip: Apply for the Waiver Before Your Permit Is Issued The SDC waiver covenant must be recorded before your building permit is issued. You cannot add it retroactively. Submit the covenant application at the same time as your building permit application to ensure you do not miss the window. |
Portland ADU Rules on Parking, Owner-Occupancy, and Short-Term Rentals
Three specific rule changes have significantly opened up ADU development in Portland over the past several years. Every homeowner planning an ADU should understand all three.
No Parking Required
Portland does not require you to add any off-street parking spaces when you build an ADU. This is a citywide rule that applies regardless of your zone or neighborhood. You do not need to eliminate existing parking to accommodate the ADU, but you also do not need to create new spaces to compensate for the additional unit.
This rule is particularly meaningful for smaller lots where carving out a new parking space would eliminate usable yard space or complicate the ADU’s placement and size.
Owner-Occupancy Not Required
Portland eliminated its owner-occupancy requirement in 2020. You do not have to live on the property to build or rent an ADU. This rule applies to both the permit process and to renting the ADU after construction. You can rent both the primary residence and the ADU as a non-owner-occupant landlord.
The SDC waiver is the one area where a distinction still exists. The waiver program requires that the units be used for long-term residential rental or owner-occupancy. It does not require the applicant to personally live on the property, but it does prohibit short-term rental use.
Short-Term Rental Rules for ADUs
If you receive the SDC waiver, neither the ADU nor the primary residence can be used as a short-term rental for the full 10-year covenant period. Short-term rental means any rental of less than 30 days, including platforms like Airbnb and VRBO.
Portland also requires a separate Type A or Type B accessory short-term rental permit for any property that rents for less than 30 days, regardless of whether an SDC waiver was used. If short-term rental income is part of your ADU plan, confirm the current permit requirements with BDS before finalizing your design and financing.
ADUs for Aging in Place and Multigenerational Living in Portland
This is the context that most Portland ADU guides skip entirely. For a large percentage of Portland families, the reason they are building an ADU is not primarily financial. It is personal.
An ADU designed for an aging parent, a family member with a disability, or a senior who wants to remain close to family without giving up independence is a fundamentally different project than an investment rental unit. The design priorities are different. The layout decisions are different. And the accessibility requirements need to be built in from the beginning rather than retrofitted later.
Suite Additions is Portland’s specialist in accessible ADU design and construction. Every ADU we build for multigenerational or aging-in-place purposes incorporates accessible design from the foundation up: wider doorways to 36-inch clear opening, zero-threshold entries, roll-in showers, ADA-height fixtures, and accessible kitchen configurations. These are not afterthoughts. They are designed before the permit is submitted.
An accessible ADU built correctly the first time avoids the costly and disruptive modifications that arise when mobility needs change and an existing unit was not designed to accommodate them. The accessible bathroom remodeling and door and wall widening services we provide are built into our ADU projects from day one when the client’s needs call for it.
For families planning an ADU for a parent or loved one with mobility challenges, the design decisions that matter most are covered in the Suite Additions guide Home Modifications for Aging in Place.
Common Portland ADU Permit Mistakes That Delay or Derail Projects
Most homeowners who experience permit delays did not make catastrophic errors. They made predictable, avoidable mistakes that experienced contractors catch before submission. Here is what to watch for.
Starting design before verifying feasibility. Lot constraints, setback requirements, existing tree canopy, and utility access points can fundamentally reshape an ADU design. Investing in full drawings before confirming that your site can support the plan you are envisioning creates expensive rework.
Assuming the five-foot setback is guaranteed. Five feet is Portland’s minimum in standard zones, not a universal rule. Some zones require larger setbacks. Designing to the minimum without confirming your specific zone’s requirement is a common cause of plan review revisions.
Missing the SDC waiver window. The covenant must be recorded before the permit is issued. Homeowners who discover the waiver program after their permit is already in the system cannot add it retroactively. This is the mistake with the most significant financial consequence.
Underestimating utility complexity. If your ADU requires a new or upgraded water connection, sewer lateral, or stormwater management system, these add time and scope to the project. Sites that add more than 500 square feet of new impervious surface must manage stormwater on-site through Portland’s Stormwater Management Manual requirements.
Not accounting for tree permits. Portland’s Urban Forestry division regulates tree removal separately from BDS. Any tree removal required for ADU construction triggers a separate permit process that can add weeks to your project timeline if not planned for in advance.
Portland ADU Rules 2026: What to Do Next
Portland’s ADU rules for 2026 give homeowners more flexibility than almost any other city in Oregon. A by-right permit process, no parking requirements, no owner-occupancy requirement, and a meaningful SDC waiver program all work in your favor if you plan carefully and submit correctly.
The difference between a smooth ADU project and a frustrating one almost always comes down to the preparation that happens before the first drawing is produced. Verify your lot’s feasibility. Understand your setbacks and lot coverage limits. Confirm the SDC waiver’s current status. And if your ADU is for an aging parent or a family member with mobility needs, make sure accessibility is built into the design from the beginning rather than added as an afterthought.
Suite Additions has built accessible ADUs across the Portland metro area for families who needed more than just a construction contractor. They needed a team that understands both the permit process and the real purpose behind the project. That is what we bring to every engagement.
Ready to plan your Portland ADU? Suite Additions offers free consultations across Portland, Tigard, Beaverton, Tualatin, and Hillsboro. Contact us today and let Tim Jorgens and his team guide your project from first questions to final inspection.
Frequently Asked Questions: Portland ADU Rules 2026
1. How big can an ADU be in Portland in 2026?
A detached ADU can be up to 800 square feet by right, or up to 75 percent of the primary dwelling’s floor area, whichever is smaller. Attached ADUs follow the same 800 square foot limit in standard configurations.
2. What are the setback requirements for a Portland ADU?
The minimum setback from side and rear property lines is 5 feet for a detached ADU under Portland Zoning Code 33.205.040.D. Some zones require larger setbacks. Always confirm your specific zone’s requirements before finalizing a design.
3. Do I need to live on the property to build an ADU in Portland?
No. Portland eliminated its owner-occupancy requirement in 2020. You can build and rent an ADU as a non-owner-occupant landlord.
4. Is parking required for a Portland ADU?
No. Portland does not require any additional off-street parking when an ADU is added to a property. This applies citywide regardless of zone or neighborhood.
5. What is the Portland ADU SDC waiver?
The SDC waiver eliminates all System Development Charges for eligible ADUs under Portland City Code 17.14.070. To qualify, the property owner must sign a 10-year covenant agreeing not to use the ADU or primary residence as a short-term rental.
6. Can I use the SDC waiver if I plan to rent the ADU on Airbnb?
No. The SDC waiver is explicitly not available for ADUs used as short-term rentals. The 10-year covenant prohibits accessory short-term rental use on the entire property for the waiver’s duration.
7. How long does an ADU permit take in Portland?
Standard ADU permits with complete submittals process in four to eight weeks at BDS. Projects requiring tree permits, historic review, or land use review can take four to six months.
8. Can I build two ADUs on my Portland property?
In standard single-family zones, Portland allows one ADU per lot. Under Oregon’s middle housing rules, some properties can accommodate more total units. Check your specific zone through PortlandMaps for the rules that apply to your lot.
9. Can Suite Additions manage the Portland ADU permit process for me?
Yes. Suite Additions handles the complete permitting process for every ADU project we build, including BDS submittal preparation, SDC waiver application, and coordination through all inspection stages.
10. How do I get started with an ADU project in Portland?
Contact Suite Additions for a free in-home consultation. Tim Jorgens and his team will assess your lot, walk through your goals, and guide you through the design and permit process from beginning to end.
