Accessory Structures in Benton County, WA (2026)
2 county-level rules, plus city-specific rules for 1 city in Benton County, Washington.
Verified from official government sources
ADU Rules
Washington's HB 1337 (RCW 36.70A.681) requires Benton County to allow at least two accessory dwelling units on single-family lots inside its urban growth areas, cannot cap ADUs below 1,000 square feet, and cannot require owner-occupancy.
Benton County ADU Rules (HB 1337)
Few RestrictionsRCW 36.70A.681(1)(c)
The city or county must allow at least two accessory dwelling units on all lots that are located in all zoning districts within an urban growth area that allow for single-family homes.
Shed & Carport Rules
In the Community Center Residential District, Benton County caps a parcel's total lot coverage at 40 percent and holds detached sheds and other accessory buildings to a 10-foot setback from the rear and side property lines, under BCC 11.06.080 and 11.06.090. A shed still has to meet the same front setback that applies to the house.
Benton County Shed and Accessory Building Rules
Some RestrictionsBCC 11.06.080(c), 11.06.090(a)(1),(3)-(4)
11.06.080 PROPERTY DEVELOPMENT STANDARDS-GENERAL STANDARDS... (c) Maximum Lot Coverage. Each parcel shall have a maximum lot coverage of forty (40) percent... 11.06.090 PROPERTY DEVELOPMENT STANDARDS--SETBACK REQUIREMENTS. All lands, structures, and uses in the Community Center Residential District (CCR) shall meet the following setback requirements... (a) Setback Requirements. The following mi...
Accessory Structures by City in Benton County
1 cities in Benton County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
All Benton County ordinances
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