5 rules for unincorporated Trinity County, California.
Verified from official government sources
All of Trinity County is unincorporated, and the county allows accessory dwelling units by right in every zone that permits single-family or multifamily dwellings. ADUs and JADUs are approved ministerially within 60 days with no hearing, capped at 1,200 square feet, held to a four-foot side and rear setback and a 25-foot height limit, consistent with California state ADU law.
In unincorporated Trinity County, detached sheds are allowed in any zone and must meet setbacks of 20 feet in front, 5 feet at interior side and rear, and 10 feet at a street side or alley, capped at 25 feet in height. A one-story shed up to 750 square feet may precede the main home in rural zones.
Converting a garage into a living unit in unincorporated Trinity County is usually done as an ADU under Zoning Code Chapter 17.95. A garage or other existing accessory structure may be converted ministerially, and when a detached garage is demolished or converted to an ADU the county may not require the lost parking to be replaced, consistent with California ADU law.
Carports are regulated as detached accessory buildings in unincorporated Trinity County under Zoning Code Chapter 17.90. A detached carport must meet the accessory-structure setbacks of 20 feet in front, 5 feet at interior side and rear, and 10 feet at a street side or alley, and stay under 25 feet in height. An attached carport follows the primary dwelling's setbacks.
Trinity County adopted Ordinance No. 1375 in June 2025, creating County Code Chapter 15.27 for movable tiny homes. A movable tiny home is a transportable dwelling of 400 square feet or less, built to RV standards, allowed by right wherever single-family dwellings are. It needs a building permit and a permanent power and water connection, and must look like a house, not an RV.
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