Accessory Structures in Riverside County, CA (2026)

5 county-level rules, plus city-specific rules for 8 cities in Riverside County, California.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Riverside County. If you live within an incorporated city, that city's own rules apply — see the city list below.

ADU Rules

In unincorporated Riverside County, ADUs and Junior ADUs are governed by Ordinance No. 348, Article XIXj. Detached ADUs are capped at 1,000 sq ft and 16 feet, with 4-foot side and rear setbacks and ministerial (no-hearing) approval. State ADU Law (Gov. Code 66310-66342) overrides any stricter county rules.

Riverside County Accessory Dwelling Unit (ADU) Rules

Few Restrictions

Full ordinance details →Official source ↗

Shed Rules

Sheds and other non-habitable detached accessory structures in unincorporated Riverside County are governed by Ordinance No. 348, Section 18.18. They must meet the underlying zone's rear-yard setback, may not be closer to the front lot line than the house, may not exceed two stories or 40 feet, and may not contain a kitchen or be used for sleeping.

Riverside County Shed & Detached Accessory Building Rules

Some Restrictions

Full ordinance details →Official source ↗

Garage Conversions

Converting a garage or carport into living space in unincorporated Riverside County is treated as an ADU or Junior ADU under Ordinance No. 348, Article XIXj. No replacement parking is required when a garage, carport, or marked space is converted into an ADU or JADU, consistent with California State ADU Law.

Riverside County Garage Conversion Rules

Few Restrictions

Full ordinance details →Official source ↗

Carport Rules

A carport is a non-habitable detached accessory structure under Ordinance No. 348, Section 18.18, subject to the zone's setbacks, a two-story/40-foot height cap, and the prohibition on kitchens and overnight use. When an existing carport is converted to an ADU, Article XIXj requires no replacement parking.

Riverside County Carport Rules

Some Restrictions

Full ordinance details →Official source ↗

Tiny Homes

Riverside County has no separate "tiny home" code. A permanent tiny house on a foundation is treated as an ADU or Second Unit under Ordinance No. 348, Article XIXj; State ADU Law also requires the County to allow a manufactured home as an ADU. A tiny home on wheels (RV) generally cannot be used as a permanent residence.