Richland, WA Accessory Structures: ADU Owner Occupancy (2026)

RMC Section 23.42.020(F) makes owner occupancy a recorded condition of every accessory apartment in Richland, not just a policy preference. Before Development Services will issue the building permit that establishes the unit, the property owner must record a deed restriction with the Benton County auditor's office, in a form the planning director prescribes, describing the accessory apartment's location and size. That recorded covenant states that one of the two dwelling units, either the primary residence or the accessory apartment, is and will continue to be occupied by the property owner as the owner's principal and permanent residence for as long as the other unit is occupied by someone else or rented out.

The owner has to maintain residency at least six months out of each year, and cannot collect rent for, or allow anyone to occupy, the owner-occupied unit during the months the owner is away for the remainder of the year. The code treats a false certification of owner occupancy as a violation of the zoning ordinance in its own right, subject to enforcement action independent of any other accessory apartment requirement. Because the restriction runs with the deed, it binds subsequent owners of the property, not just the person who originally built the unit, so a buyer inherits the same six-month residency obligation.

The requirement sits alongside the separate accessory apartment permit in RMC Section 23.42.020(G), which Development Services must approve before any building permit for alterations or new construction proceeds, tying the deed restriction directly to the permitting sequence rather than treating it as a formality filed later.