Before You Build in Orange County, CA: Permit & Rule Checklist (2026)

Orange County enforces the California Swimming Pool Safety Act (Health & Safety Code §115920-115929) and adopted Ordinance No. 19-006 requiring both primary and secondary pool barriers for all residential pools in unincorporated areas with water depth exceeding 18 inches.

OCCO Zoning Code Section 7-9-137.5 regulates fence and wall heights in unincorporated Orange County. Fences in front setback areas are limited to 3.5 feet; side and rear fences may reach 6 feet. Visibility triangles at intersections have additional restrictions.

Building permits are required for fences and walls over 6 feet in height in unincorporated Orange County. Retaining walls over 4 feet retaining level earth, or any retaining wall subject to surcharge, also require permits and engineered plans through OC Development Services.

Shared boundary fences in unincorporated Orange County are governed by California Civil Code Section 841, the Good Neighbor Fence Act. Adjoining property owners are presumed equally responsible for reasonable costs of construction, maintenance, and replacement of boundary fences.

Retaining walls in unincorporated Orange County require building permits and engineered plans when retaining level earth over 4 feet, retaining any slope, or subject to surcharge loads. The OC Grading Manual and Building Code govern design and construction standards.

Unincorporated Orange County requires every pool/spa deeper than 18 inches to be enclosed by a barrier at least 60 inches (5 ft) high under California Health & Safety Code §115923 and CBC §3109. OC Ordinance 19-006 additionally requires a secondary safety feature (mesh fence, cover, or alarm).

Unincorporated Orange County allows ADUs on any residentially zoned lot under OC Zoning Code (Title 7, Division 9) and California Government Code §65852.2 (ADUs) and §65852.22 (JADUs). State law preempts most local restrictions: minimum 800 sqft, 16 ft height, and 4 ft side/rear setbacks must be allowed by right.

Unincorporated Orange County allows the conversion of an existing garage, carport, or accessory structure into an accessory dwelling unit (ADU) under Section 7-9-90 of the Codified Ordinances and California Government Code Section 65852.2. A garage-conversion ADU may be the size of the converted structure plus up to 150 square feet for ingress/egress, processed ministerially, and the parking space lost in the conversion does not need to be replaced.

Carports in unincorporated Orange County are governed by Section 7-9-70.3(d) of the Codified Ordinances, which requires carports to comply with main-building setbacks and provides specific rules for entry location, alley/driveway access, and placement in rear or interior side yards. Section 7-9-70.3(c)(2) requires 28 feet of unobstructed maneuvering area in front of a carport, and each covered space must be at least 10 feet by 20 feet under Section 7-9-70.3(a)(1). Building permits are required under Title 7 (adopted CBC).

Unincorporated Orange County exempts one small detached non-habitable accessory structure - a shed - per 7,200 square feet of building site area from accessory-structure standards under Section 7-9-116.1(h)(1) of the Codified Ordinances, provided it is under 120 square feet, no taller than 8 feet, set at least 3 feet from rear and side property lines, set at least 6 feet from another building, and not located in any front yard. Sheds beyond that allowance are accessory structures regulated by Section 7-9-116.1.

Recreational fire pits are allowed in unincorporated Orange County subject to OCFA fire code requirements and SCAQMD no-burn day restrictions. Gas-fueled fire pits are generally unrestricted, while wood-burning fire pits must comply with Check Before You Burn requirements from November through February.

Outdoor burning is heavily restricted in unincorporated Orange County under the California Fire Code as adopted by OCFA. Open burning of yard waste, trash, or debris is prohibited. Recreational fires in approved containers may be permitted under strict conditions, but are banned during red flag warnings or high-wind events.

Orange County adopted its Water Efficient Landscape Ordinance (WELO) on March 14, 2016, implementing California's Model WELO for all new construction and major landscape renovations in unincorporated areas. Projects must submit landscape and irrigation plans complying with state water efficiency standards.

Orange County maintains trees within public rights-of-way in unincorporated areas on a 2.5-year trimming cycle. Private property owners are responsible for maintaining trees at their own expense and must not allow trees to obstruct sidewalks, streetlights, or traffic signs.

OCCO Zoning Code Section 7-9-69 establishes the Protected Tree Ordinance for unincorporated Orange County. Protected trees with a diameter at breast height (DBH) of 5 inches or more cannot be removed without a Protected Tree Removal or Damage Permit. Replacement ratios of at least 5:1 apply.