Accessory Structures in Butte County, CA (2026)
5 county-level rules, plus city-specific rules for 1 city in Butte County, California.
Verified from official government sources
ADU Rules
Butte County permits accessory dwelling units (ADUs) and junior ADUs in unincorporated areas served by municipal water and sewer, with ministerial approval, 4-foot side/rear setbacks, and size caps of 500 sq ft (JADU) or 1,200 sq ft (detached ADU); short-term rentals under 30 days are prohibited.
Butte County ADU rules (Section 24-172)
Heavy RestrictionsButte County Code section 24-172 (Accessory Dwelling Units and Junior Accessory Dwelling Units), subsections A, B, C, E, and H
A. Purpose. The unincorporated area of Butte County is predominantly rural and includes large areas of actively farmed agricultural land, as well as timber producing land. Only very limited areas adjacent to the City of Oroville are served by water and sewer service providers. Butte County allows second units in most zones that allow residences (see Section 24-172.2). This section establishes s...
ADU Impact Fees
Butte County cannot charge an impact fee on an accessory dwelling unit or junior ADU under 750 square feet, and any fee on a larger ADU must scale proportionately to the primary dwelling's square footage under Section 24-172(D)(3).
Butte County Waives ADU Fees Under 750 Sq Ft
Light RestrictionsButte County Code of Ordinances § 24-172(D)(3)
A local agency, special district or water corporation shall not impose any impact fee upon the development of an accessory dwelling unit or a junior accessory dwelling unit that is less than seven hundred fifty (750) square feet. Any impact fee charged for an accessory dwelling unit of seven hundred fifty (750) square feet or more shall be charged proportionately in relation to the square foota...
ADU Rental Restrictions
An accessory dwelling unit or junior ADU in unincorporated Butte County must be rented under the same rental term as the primary dwelling, closing off short-term or transient rental of the accessory unit under Section 24-172(G)(7).
Butte County ADU Rental Term Matches Main House
Light RestrictionsButte County Code of Ordinances § 24-172(G)(7)
7.Rental Term. The rental term for an accessory dwelling unit or a junior accessory dwelling unit is the same as for the primary dwelling.
Shed & Carport Rules
One-story detached sheds under 120 sq ft do not require a Butte County building permit, but they must meet zoning setbacks; any electrical, plumbing, or gas utilities serving the shed do require permits.
Butte County shed permit and setback rules
Some RestrictionsButte County Department of Development Services Form DBP-20 (Revised 2/18/26); Butte County Code section 26-3.1 and California Building Code section 105.2
WORK EXEMPT FROM BUILDING PERMITS. Butte County Code, Section 26-3.1 and California Building Code Section 105.2. Exemptions from permit requirements shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of current code or any other laws or ordinances of this jurisdiction. Building permits shall not be required for the following: Building...
Garage Conversions
Butte County allows conversion of an existing garage or accessory structure into an ADU with no required setback and no replacement parking, provided the parcel is within a water and sewer service area and the conversion meets building code.
Butte County garage-to-ADU conversion rules
Some RestrictionsButte County Code section 24-172(H)(1)(a) and section 24-172(H)(3)(c) (Setbacks and Parking for Accessory Dwelling Units)
H. Development Standards. 1. Setbacks. The following setbacks are applicable for all accessory dwelling units: a. An existing structure may be converted into an accessory dwelling unit or junior accessory dwelling unit without a setback. If the existing structure requires an expansion of 150 square feet or less to accommodate an accessory dwelling unit or junior accessory dwelling unit, the set...
Accessory Structures by City in Butte County
1 cities in Butte County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
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