Hesperia, CA Accessory Structures: ADU Rules (2026)
ADU rules in Hesperia, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Review type
- Ministerial, no hearing required
- Detached ADU max size
- 1,200 sq ft livable area
- New ADU setback
- 4 ft side and rear yard
- Height limit
- 16 ft (18 ft near transit)
Summary
Hesperia issues accessory dwelling unit permits ministerially under its Development Code, which sets a four-foot side and rear yard setback, size caps, and height limits implementing state ADU law.
A detached accessory unit shall not exceed one thousand two hundred (1,200) square feet of livable floor area (excludes garage and any accessory structure) on any parcel. Accessory dwelling units attached to the principal unit may be up to fifty (50) percent of the area of the principal unit, up to a maximum of one thousand (1,000) square feet, except that if the principal unit has a floor area of one thousand six hundred (1,600) square feet or less, an attached accessory dwelling unit shall conform to the provisions of Section 16.12.360(E)(6), below. The area of an accessory dwelling unit is in addition to and shall not be considered as part of the allowable accessory building area authorized under Article X of Chapter 16.20. No accessory dwelling unit shall be less than one hundred and fifty (150) square feet in area. Further, a recreational vehicle, does not qualify for use as an accessory dwelling unit.3.Independent access to an attached accessory dwelling unit is required and shall not be located on the same wall plane elevation as the access to the primary dwelling.4.For new attached or detached accessory dwelling units, a minimum four-foot side yard and four-foot rear yard setback is allowed. The front yard and street side yard standards for the primary unit shall apply to the accessory dwelling unit.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 24 Update 2).
Full Breakdown
Hesperia processes ADU permits ministerially, implementing state Government Code sections 66310-66342, which override conflicting local limits. Detached units may not exceed 1,200 square feet of livable area; attached units are capped at 50% of the primary home's floor area, up to 1,000 square feet. New attached or detached ADUs need only a 4-foot side and rear yard setback, waived entirely for conversions of existing structures or garages. Height is capped at 16 feet (18 feet near major transit). One ADU plus one junior ADU is allowed per single-family lot, and the city must act on a complete application within 60 days.
Violations & Fines
Building or occupying an ADU without city approval is a code violation enforceable under Chapter 1.12; unpermitted units can be red-tagged and must be legalized or removed before they can be rented.
Frequently Asked Questions
Does Hesperia require a public hearing for an ADU permit?
Can Hesperia enforce a stricter ADU limit than state law allows?
Sources & Official References
Other rules in Hesperia
How Hesperia compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Hesperia to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in San Bernardino County handle adu rules.