Accessory Structures in Richland, WA (2026)
3 verified accessory structures rules for Richland, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
In the City of Richland, Washington, a single-family lot can add one accessory apartment under RMC Section 23.42.020, capped at 40 percent of the primary dwelling's floor area and set between 200 and 800 square feet, with its own kitchen and bathroom and no more than two bedrooms.
Richland ADU Zoning Rules and Size Caps
Some RestrictionsRichland Municipal Code § 23.42.020(A), (C), (D)
One accessory apartment per single-family dwelling unit is allowed within all single-family zones within the city under the following conditions: A. Accessory apartment units established in conformance with the provisions of this section may be allowed as permitted uses on lots zoned for single-family dwellings. No more than one accessory apartment unit per legal lot is permitted and it must be...
ADU Owner Occupancy
In the City of Richland, Washington, before a building permit for an accessory apartment is issued, the owner must record a deed restriction with the Benton County auditor covenanting that either the primary home or the accessory unit remains the owner's principal residence. Falsely certifying that occupancy is treated as a zoning violation.
Richland ADU Owner-Occupancy Deed Restriction
Significant RestrictionsRichland Municipal Code § 23.42.020(F)
F. Prior to the issuance of a building permit establishing an accessory apartment unit, the property owner shall record a deed restriction with the Benton County auditor's office. The document shall be in a form prescribed by the planning director and include a description of the location and size of the accessory apartment unit and a covenant that one of the dwelling units is, and will continu...
Shed & Carport Rules
In the City of Richland, Washington, a detached tool or storage shed no larger than 200 square feet (IRC) or 120 square feet (IBC) skips the full building permit under RMC § 21.01.020(D)(1), but it still needs a no-fee location placement permit before construction. Bigger sheds trigger RMC § 23.38.020's setback tiers, which run as tight as 1.5 feet for small, low sheds.
Richland Shed Size, Setback & Permit Rules
Some RestrictionsRichland Municipal Code § 21.01.020(D)(1)
1. One-story detached accessory structures used as tool and storage sheds, playhouses, and similar uses, provided the floor area does not exceed 200 square feet (IRC) and 120 square feet (IBC), are exempted from the requirements for a building permit. A permit for location placement of such exempt structures shall be issued by the City of Richland prior to construction or erection of these stru...
Looking for Benton County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Richland city rules.
Accessory Structures in Benton County →