If you are looking for long-term rental income or want to house family and friends, you can create an accessory dwelling unit (ADU) on property you own. ADUs are an additional, smaller dwelling on the same property as your single-family home.

Examples include:

• A “mother-in-law” cottage
• A basement apartment
• An apartment over the garage

Interested in adding more units on your property? Check out the City’s Middle Housing  regulations.

Where You Can Create an ADU

Accessory dwelling units are allowed as a special use in the following land use zones:

• Residential Agriculture (RA)
• Single-family Residential (RS)
• Multiple Family Residential 1 (RM1)
• Multiple Family Residential 2 (RM2)
• Multiple Family Residential 3 (RM3)
• Commercial Office (CO)
• Retail Commercial (CR)
• General Commercial (CG)
• Central Business District (CB)
• Industrial Commercial (IC)
• Industrial Park (IP)
• General Industrial (IG)
• Neighborhood Hub (NH)
• Mixed Use-I (MU-I)
• Mixed Use-II (MU-II)
• Mixed Use-III (MU-III)
• Mixed Use-Riverfront (MU-R)
• Edgewater/Second Street Mixed-Use Corridor (ESMU)

Characteristics of an ADU

Some of the defining traits of an accessory dwelling unit include:

• Only one ADU per lot
• No off-street parking spaces are required for ADUs
• Square footage is limited to 900 square feet or 75% of the main house, whichever is less
• Height is limited to 25 feet tall for detached ADUs
• An ADU must include both a bathroom and a kitchen
• Does not have a direct interior connection to the main house

You can review all the specifications in Salem Revised Code 700.007.

Prohibited uses in ADUs

ADUs cannot be used for short-term rentals. ADUs are intended to provide permanent housing whether rent is charged or not. Tenants who are renting must be renting for at least 30 days at a time. Tenants can live in an ADU permanently.

ADUs must be permanently built structures; they cannot be on wheels.

A guest house is not an ADU

A guest house is a detached accessory building maintained for the purpose of providing temporary and free living accommodations but remains dependent upon the main dwelling for cooking or bathroom facilities or both. Unlike a guest house, an ADU must be an independent dwelling unit having both a kitchen and a bath. A guest house is intended for temporary lodging and not as a place of residence. Rent may not be charged for a guest house. A guest house may be converted to a dwelling unit with appropriate building permits and upgrades

Process for Getting ADU Approval

ADU is considered a special use, so no land use application process is required as long as you can meet the special use standards. You do need a building permit. Off-street parking spaces are not required for ADUs.

• Apply for building permits using the online permit process. You will need the following applications:
  
  • Residential permit application
  • Electrical permit application
  • Mechanical permit application
  • Plumbing permit application
• Complete a water meter sizing worksheet to ensure that you have adequate water pressure for both houses.

The City also offers ready-build plans that you can use to develop an ADU on your property. You can download the plans for free and use them with the current building permit application process.

System Development Charges (SDCs)

SDCs have been waived for ADUs by Salem City Council.

Additional Information about Creating and Working with ADUs

• AccessoryDwellings.org: Information about ADUs.
• Salem Rental Housing Association: Membership organization to help people understand landlord laws and follow good business practices.
• The Center for Universal Design: Information about designing your space so it is useable for all people without adaptation.

Background on ADUs

The City started to consider allowing accessory dwelling units in Salem in 2016 as a first step of a multi-year project to address Salem’s projected deficit of land for multifamily housing. The projected 207-acre deficit was identified in the Salem Housing Needs Analysis. That analysis examined if there was enough land in Salem’s portion of the urban growth boundary to meet housing needs over the next 20 years.

Project Documents

• Salem Housing Needs Analysis