Placer County, CA Accessory Structures: ADU Rules (2026)
ADU rules in Placer County, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- County Code Section
- Placer County Code 17.56.200
- State Law
- California Gov. Code 66310 et seq. (formerly 65852.2)
- Units Allowed
- 1 primary + 1 ADU + 1 JADU per residential parcel
- Max Detached ADU Size
- 1,200 sq ft
- Setbacks
- 4 ft from side and rear lot lines
- Parking
- Max 1 space per ADU; exempt within 1/2 mile of transit
Summary
In unincorporated Placer County, residential parcels may have one primary dwelling, one accessory dwelling unit (ADU) and one junior ADU. Detached ADUs may reach 1,200 sq ft; attached ADUs up to 50% of the primary dwelling. There is no minimum parcel size, setbacks are 4 ft from side and rear lot lines, and parking is capped at one space per ADU.
One ADU and one Junior ADU are allowed per parcel in addition to the primary dwelling. Detached ADUs may be up to 1,200 sq. ft. The minimum required setback for a new construction ADU on a single-family property is 4 feet from the rear and interior side property lines.
Full Breakdown
200 (Accessory and junior accessory dwelling units), implementing California's state ADU law (Gov. 2 effective January 2025). Every residentially zoned parcel may have one primary dwelling, one ADU and one junior ADU (JADU). A detached ADU may be up to 1,200 square feet regardless of the size of the primary structure; an attached ADU is limited to 50% of the existing primary dwelling. A JADU is capped at 500 square feet and must be created within the walls of the proposed or existing primary dwelling.
There is no minimum parcel size, though adequate water and sewer or septic must be demonstrated. The required setback is four feet from side and rear lot lines, and the height limit is set by the zone district but cannot be less than 16 feet. Parking may not exceed one space per ADU, and parking is exempt where the ADU is within one-half mile of transit or part of a conversion. A building permit is always required. 200). Renting an accessory home for 30 days or less is prohibited. ADUs in the Lake Tahoe portion of the county are subject to additional Tahoe Regional Planning Agency (TRPA) coverage and permit rules.
Violations & Fines
Building or occupying an ADU or JADU without the required building permit, or exceeding the size, height or setback standards in Placer County Code Section 17.56.200, is a zoning and building code violation enforced by Placer County Code Enforcement and Building Services. Operating an accessory home as a short-term rental of 30 days or less is prohibited and citable. Violating the JADU owner-occupancy requirement is also enforceable. Remedies range from a notice to correct, permit revocation and stop-work orders to civil penalties and abatement; unpermitted construction must typically be permitted retroactively or removed.
Frequently Asked Questions
How big can an ADU be in unincorporated Placer County?
Is there a minimum lot size for an ADU in Placer County?
Sources & Official References
Other rules in Placer County
How Placer County compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Placer County to another location·View the California accessory structures overview
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