Create Dual Living or Guest Housing

​You can provide temporary or permanent housing for two families on one lot in several ways.  

Examples of dual living

Duplex: A building containing two independent dwelling units. Each dwelling unit provides complete, independent living facilities for one or more people, including permanent provisions for living, sleeping, eating, cooking, and sanitation.

Two houses on a lot:  Two detached, independent dwelling units on a lot. Each dwelling unit provides complete, independent living facilities for one or more people, including permanent provisions for living, sleeping, eating, cooking, and sanitation.

Guest house: 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. Temporary uses are limited in duration to no more than six months in a calendar year. A guest house may not be converted to a dwelling unit. Guest houses are classified as accessory structures and must comply with all applicable development standards for accessory structures.

Two-family shared housing: The two-family shared housing option allows an owner-occupied single-family dwelling to be converted to add a second dwelling unit, similar to a duplex. For two-family, shared housing, only one of the two units may be occupied by a family that does not include an owner of the building. At least 60 percent of the building’s habitable space prior to conversion must be included within one of the dwelling units. Each of the dwelling units has to include a minimum area of 600 square feet, and not more than 60 square feet of floor area can be added to the building.

Allowances by zone

Dual living uses are commonly allowed in residential zoning districts as shown below:

Zone type Duplex ​Two house on a lotGuest house Two-family shared housing
RA (Residential Agriculture) Allowed only on a corner lot or a lot whose side abuts property other than a street or alley in a Commercial (C) or Industrial (I) zone, and the entire lot is located within 165 feet of the C or I zone (minimum lot size is 7,000 square feet) ​Not allowedAllowed Special use
RS (Single-Family Residential) Allowed only on a corner lot or a lot whose side abuts property other than a street or alley in a Commercial (C) or Industrial (I) zone, and the entire lot is located within 165 feet of the C or I zone (minimum lot size is 7,000 square feet) ​Not allowedAllowed Special use
RD (Duplex Residential) Allowed (minimum lot size is 7,000 square feet) ​Allowed (minimum lot size is 7,000 square feet)Allowed Not allowed
RM1 (Multiple Family Residential 1) Allowed (subject to minimum and maximum dwelling unit density Not allowed Not allowed
RM2 (Residential Family Residential 2) Allowed (subject to minimum and maximum dwelling unit density requirements) ​Allowed (subject to minimum and maximum dwelling unit density requirements)Allowed Not allowed
RH (High-Rise Residential) Allowed ​Allowed Allowed Not allowed
CO (Commercial Office) Allowed ​Not allowedAllowed Not allowed

Illegal dwelling units

In some cases, additional dwelling units may have been added to a single-family dwelling without approval, and the alterations may not comply with zoning regulations. It is a violation to use a single-family home in a manner not allowed in the zoning code. Illegal alterations to single-family dwellings that do not comply with zoning regulations are not considered nonconforming or “grandfathered” uses, and they may be required to be removed and restored. Illegal uses may not be rebuilt following damage or destruction.

Apply for a building permit

To build a duplex, two houses on a lot, or a guest house or to convert your single-family home to two-family shared housing, you need to apply for a residential building permit.

Contact us

Planning DivisionCommunity Development Department
Monday–Friday
8:00 a.m.–5:00 p.m.
555 Liberty ST SE RM 305
Salem OR 97301
Phone: 
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