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

Ontario pool barriers must meet CA Health and Safety Code 115920 (Pool Safety Act). A 60-inch enclosure, self-closing gate, and 2 of 7 drowning-prevention features are required on new or remodeled pools.

Ontario requires a permit for any retaining wall over 4 feet (footing to top) or carrying a surcharge such as a slope or driveway. Engineered plans by a licensed California civil or structural engineer are required.

Shared Ontario fences are governed by California Civil Code 841, the Good Neighbor Fence Act. Adjoining owners are presumed to share costs equally after 30 days of written notice to the neighbor.

Ontario limits residential fence heights under the Development Code. Typical maximums are 6 feet rear/side, 3 feet front, and 42 inches in sight-distance triangles at corners. Taller fences need a variance.

Ontario requires a building permit for masonry walls and any fence over 7 feet under the California Building Code. Retaining walls over 4 feet also require permits. Standard 6-foot wood or vinyl fences typically do not.

Ontario hot tubs and spas require a building permit, electrical permit, bonding to Article 680, and either a locking safety cover meeting ASTM F1346 or full pool-barrier compliance under state law.

Ontario requires a building permit, plumbing permit, electrical permit, and plan check before any pool or spa construction under the California Building Standards Code and Ontario Municipal Code.

Above-ground pools in Ontario deeper than 18 inches need a building permit, barrier compliance, and electrical bonding. Removable mesh fencing or a self-latching ladder gate typically satisfies code.

Ontario pools must comply with the California Swimming Pool Safety Act at H&S Code 115920, which requires an approved barrier or combination of safety features around any residential pool or spa.

Ontario residential pools must meet state drowning-prevention safety features, anti-entrapment drain covers under the Virginia Graeme Baker Act, and California Building Code electrical bonding rules.

Ontario allows garage-to-ADU conversions under Gov Code 65852.2 with no replacement parking required. Non-ADU conversions to living space still need a building permit and must replace covered parking.

Ontario must allow ADUs and JADUs under California Gov Code 65852.2 and 65852.22 on all single-family and most multifamily lots. Approval is ministerial within 60 days, with no minimum lot size.

Foundation-built tiny homes qualify as ADUs under Gov Code 65852.2 in Ontario. Tiny homes on wheels are treated as RVs or park trailers and cannot be used as permanent dwellings on residential lots.

Ontario allows carports on residential lots subject to zoning setbacks and a building permit for any carport 200 sq ft or larger. Properly sized carports count toward required covered parking.

Ontario follows CRC Section R105.2, exempting one-story detached sheds under 120 sq ft from a building permit. Sheds must still meet zoning setbacks, height limits, and trade permits for electrical.

Ontario allows backyard fire pits under the California Fire Code as adopted. Wood pits must sit 25 feet from structures and be attended. SCAQMD no-burn days override local rules.

Open burning of yard waste, trash, or debris is banned in Ontario under the adopted California Fire Code and SCAQMD Rule 444. Only recreational fires in approved pits and BBQ cooking are allowed.

Private yard trees in Ontario can usually be removed without a city permit, but parkway street trees are city-owned and need a Public Works permit. Commercial landscape plan trees require plan revision.

Ontario owners must trim trees so branches clear sidewalks, streets, and signs. Parkway street trees are city-owned and require a Public Works permit to prune, plant, or remove.

Ontario's Water Shortage Contingency Plan limits outdoor watering to assigned days and cool hours. AB 1572 bans potable water on non-functional turf at commercial and HOA sites starting January 2027.