Everything homeowners need to know about building an accessory dwelling unit in Salem - size limits, setbacks, permits, and the fee exemption that makes Salem one of the least expensive Oregon cities to add one.
Last verified: August 2026
8/10 · Very ADU-friendly
900 sq ft*
Max ADU size
25 ft
Max height
Not required
Owner-occupancy
By-right
Permit type
This page summarizes Salem's accessory dwelling unit standards under Salem Revised Code Chapter 700 (Special Use Provisions) for general reference - it is not legal advice. Regulations change; always confirm current requirements with the City of Salem Planning Division before designing or applying for permits. See sources below.
Zoning & size requirements
What you're allowed to build
ADU type
Max size
Max height
Notes
Detached (new build or garage conversion)
900 sq ft or 75% of the main dwelling's gross floor area, whichever is smaller
Common approach for above-garage or internal conversions
Allowed zoning districts
ADUs are allowed with a single-family home, manufactured home, or zero-side-yard dwelling in Salem's residential zones, and in most commercial, industrial, and neighborhood-center mixed-use zones. Confirm your zone with the Planning Division.
Additional standards
Setbacks, parking & other rules
Setbacks
3 ft from side property lines; 5 ft from rear property lines
Lot coverage
Combined coverage of the house, garage, ADU, and other accessory structures is capped at 60% of the lot
Parking
No additional off-street parking required
Units per lot
1 ADU permitted in addition to the primary dwelling
Owner-occupancy
Not required
Building code
Must meet Oregon Residential Specialty Code dwelling-unit standards
Rental license
No separate rental license, but ADUs can't be used as short-term rentals; if rented, the minimum lease term is 30 days
Ordinance history
How Salem's ADU rules got here
2016Housing Needs Analysis. The city's analysis projected a roughly 207-acre, nearly 2,900-unit shortfall of land designated for multifamily housing over 20 years, prompting Salem to look at ADUs as a first step.
2017Ordinance Bill No. 10-17. Given first reading May 22, 2017, it allowed ADUs as a special use citywide and set the 900 sq ft/75%, 25 ft height, and 3 ft/5 ft setback standards still largely in place today. The same year, Oregon's SB 1051 required cities over 2,500 people to allow at least one ADU per single-family lot statewide.
2019Oregon HB 2001. Signed August 8, 2019, the statewide law barred owner-occupancy and off-street parking requirements for ADUs.
Jan 2022HB 2001 compliance update. City Council formally adopted code changes on January 24, 2022, effective March 16, 2022, confirming Salem's ADU rules complied with the statewide ban on owner-occupancy and parking requirements.
Nov 2022Special-use provisions amended. A further ordinance clarified that ADUs are intended as permanent housing, barred short-term rental use, and set a 30-day minimum rental term.
Oct 2023Ready-Build ADU plans launch. Salem began offering free downloadable designs for detached ADUs under 600 sq ft, adapted from plans the City of Eugene had already developed and shared.
Salem also exempts ADUs from System Development Charges, the city's term for infrastructure impact fees - a policy that, together with the free Ready-Build plans, keeps Salem's out-of-pocket city fees among the lowest of Oregon's larger cities for an ADU. As the state capital, Salem is also where SB 1051 and HB 2001 themselves were written and signed into law. Oregon's Department of Land Conservation and Development reviews city ADU codes for compliance with state law; Salem's code hasn't been flagged for falling short.
Permit process
How Salem ADU permitting works
1
Pre-application check
Confirm your zone and lot eligibility with Salem's Planning Division before you design.
2
Choose a Ready-Build plan or go custom
A free, downloadable Ready-Build plan for a detached ADU under 600 sq ft can skip much of the design and plan-review process.
3
Prepare your plan set
Site plan, floor plans, elevations, and the calculation showing you're within the 900 sq ft / 75% cap.
4
Submit for a building permit
Salem processes ADUs as a building-permit matter; no special or conditional use permit is required.
5
Confirm your SDC exemption
ADUs are exempt from Salem's System Development Charges; standard building permit and plan-review fees still apply.
6
Construction & inspections
Once your permit issues, schedule the standard framing, plumbing, electrical, and final inspections.
Fees and review timelines change periodically - confirm current figures with the City of Salem Planning Division before budgeting.
Budgeting
What it costs to build an ADU in Salem
Garage conversion
Roughly $65,000-$145,000, the least expensive path since the shell already exists
Basement conversion
Roughly $95,000-$195,000, depending on existing ceiling height and utility access
New detached ADU
Roughly $145,000-$275,000+ for a code-compliant, fully finished freestanding unit
System Development Charges (SDCs)
Exempted for ADUs citywide, a savings that can run into the tens of thousands of dollars compared with a standard new dwelling
Ready-Build plan
Free download for a detached ADU under 600 sq ft; standard building permit and plan-review fees still apply
These are general ranges from local contractor estimates and regional reporting, not quotes - actual cost depends heavily on lot conditions, finishes, and whether utilities need to be extended. Salem's SDC exemption is one of the more concrete cost advantages among Oregon's larger cities, but confirm it still applies to your project at the time you permit, since fee policies get revisited.
Before you apply
Tips for a smooth approval
Start with the free Ready-Build plans. If a sub-600-sq-ft detached ADU works for your lot, it's the fastest and cheapest path through permitting.
Confirm your SDC exemption before you budget. It's one of the largest cost advantages Salem offers, but verify it still applies at the time you permit.
Watch the 75%-of-house rule, not just the 900 sq ft cap. On a smaller home, 75% of your living area may cap your ADU well under 900 sq ft.
Decide on your rental plans early. Salem requires a 30-day minimum rental term and bars short-term rental use of ADUs, so short-term-rental income isn't an option here.
Mind the 60% lot coverage limit. On a lot that's already built close to capacity, this can constrain your ADU more than the setbacks do.
FAQ
Common questions
Do I need to live on the property to build an ADU in Salem?
No. Salem confirmed its code complies with Oregon's statewide ban on owner-occupancy requirements for ADUs as part of a January 2022 code update.
How many ADUs can I build on one lot in Salem?
One ADU is allowed in addition to the primary dwelling.
Do I need extra parking for an ADU?
No. Oregon state law bars cities from requiring off-street parking for ADUs, and Salem's code reflects that.
What's the maximum size for a detached ADU in Salem?
900 sq ft or 75% of your main home's gross floor area, whichever is smaller, with a 25 ft height limit.
How long does the permit process take?
Salem processes ADUs as a standard building permit, with no special or conditional use permit needed. Timelines depend on application completeness - confirm current estimates with the Planning Division.
How much does an ADU cost to build in Salem?
Garage conversions run roughly $65,000-$145,000, basement conversions roughly $95,000-$195,000, and new detached units roughly $145,000-$275,000+, based on local contractor estimates and regional reporting. Salem's SDC exemption for ADUs removes a cost that applies to most other new residential construction.
Does Salem really waive System Development Charges for ADUs?
Yes, ADUs are currently exempt from Salem's System Development Charges. Fee policies can be revisited by City Council, so confirm the exemption still applies at the time you permit.
Does Salem offer pre-approved ADU plans?
Yes. Salem's Ready-Build Plans program, launched in October 2023, offers free downloadable designs for detached ADUs under 600 sq ft, adapted from plans originally developed by the City of Eugene.
Can I rent my ADU out on Airbnb or a short-term rental platform?
No. Salem's code bars short-term rental use of ADUs and requires a minimum 30-day lease term if the unit is rented.
