Accessory Structures in Rialto, CA (2026)
9 verified accessory structures rules for Rialto, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Rialto allows one ADU plus one junior ADU per single-family lot with ministerial approval within 60 days under Rialto Municipal Code Section 18.10.070. Detached ADUs are limited to 16 feet in height, four-foot side and rear setbacks, and 1,200 square feet maximum.
ADUs allowed citywide; ministerial approval in 60 days
Some RestrictionsCity of Rialto ADU program page; Rialto Municipal Code Section 18.10.070
An ADU is a secondary housing unit that is built on the same lot as the primary residence. ... Development standards for ADUs, including height limits, size limits, lot coverage, and design guidelines can be located in the Rialto Municipal Code, Section 18.10.070. ... All detached accessory dwelling units require separate gas, water, and electric meters. All new detached dwellings require solar...
ADU Permits
ADU permits are issued by the Rialto Building & Safety Division (150 S Palm Ave). State law (Gov. Code §66317) requires the city to act on a complete ADU application within 60 days, ministerially, with no discretionary hearing. Plans must comply with the California Building Standards Code (effective 2025 edition as of Jan. 1, 2026) and RMC Title 15.
ADU Permits in Rialto
Some RestrictionsADU Impact Fees
ADUs under 750 sq ft are exempt from all impact fees in Rialto by force of state law (Cal. Gov. Code §66314(f)(3)). ADUs 750 sq ft or larger may be charged impact fees only proportionally to the primary dwelling's square footage. School-district fees are separately governed.
ADU Impact Fees in Rialto
Few RestrictionsADU Owner Occupancy
Rialto cannot impose an owner-occupancy requirement on ADUs permitted between Jan. 1, 2020 and Jan. 1, 2025 (Cal. Gov. Code §66314(a)(6)). Owner-occupancy is required for Junior ADUs (JADUs) under Cal. Gov. Code §66333 — owner must live in either the main house or the JADU.
ADU Owner-Occupancy in Rialto
Few RestrictionsADU Rental Restrictions
Rialto cannot ban ADU rentals, but state law (Cal. Gov. Code §66314(a)(6)) prohibits renting an ADU for less than 30 days. Long-term rentals are permitted by right; short-term vacation rentals in ADUs are not allowed under state law statewide.
ADU Rental Restrictions in Rialto
Some RestrictionsShed Rules
Rialto lists accessory buildings and gazebos among work requiring a building permit. Under Municipal Code Section 18.52.030, detached accessory buildings may occupy at most 25 percent of the rear yard and need 10 feet of separation from the house if over 120 square feet.
Sheds need permits; rear-yard coverage capped at 25 percent
Some RestrictionsRialto Municipal Code Section 18.52.030 - Location of accessory buildings
An accessory building may be located within five feet of any interior property line adjacent to the rear yard area. ... An accessory building having more than one hundred twenty square feet of roof area shall be separated from the main structure on the lot a minimum distance of ten feet.
Garage Conversions
Rialto ministerially approves conversion of an existing, legally permitted garage into an ADU with no new setbacks and no replacement parking, but the garage door must be replaced with windows or doors matching the home. Unpermitted units built before 2020 can be legalized under AB 2533.
Garage-to-ADU conversions allowed; garage door must be removed
Some RestrictionsCity of Rialto, Public Information Resource for AB 2533 and Third Party Inspection; Rialto Municipal Code Section 18.10.070(K)
Unpermitted Accessory Dwelling Units (ADU) or Junior Accessory Dwelling Units (JADU) constructed before January 1, 2020 may request to apply the provisions of Government Code 66332. Before making the request to the city and submitting an application for a permit, the homeowner may obtain a confidential third-party code inspection from a licensed contractor to determine the unit's existing condi...
Carport Rules
Rialto's Building and Safety standard bars using a residential patio cover as a carport or garage, and R-1 zoning limits private garages to a three-automobile capacity with an 18-foot setback when a side-yard garage opens onto the street.
Patio covers cannot serve as carports; garages capped at three cars
Some RestrictionsCity of Rialto Department of Building & Safety, Residential Patio Covers standard (Rev. 02-18-16)
Patio covers are defined as one-story structures, not exceeding 12 feet in height, that are used only for recreational, outdoor living purposes and not as carports, garages, storage rooms, habitable rooms, or 2nd. floor sun decks or balconies. Patio slabs WITHOUT an overhead structure do NOT require building permits. However, if footings are to be poured with the slab to accommodate a future pa...
Tiny Homes
Tiny homes in Rialto are regulated either as ADUs under California Government Code §65852.2 (state ADU law) and Rialto Municipal Code Title 18, or as RVs/manufactured housing under state HCD rules. Permanent tiny homes on foundations qualify as ADUs and benefit from California's ministerial-approval preemption.
Tiny Homes in Rialto, CA
Some RestrictionsLooking for San Bernardino County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Rialto city rules.
Accessory Structures in San Bernardino County →