Los Banos, CA Accessory Structures: ADU Rules (2026)
ADU rules in Los Banos, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Detached ADU height cap
- 16 ft
- Detached ADU side/rear setback
- 4 ft
- Max size, studio/1BR
- 850 sq ft
- Max size, 2BR
- 1,000 sq ft
- Review process
- ministerial, 60 days
- Minimum lot size
- none required
Summary
California's ministerial ADU law runs the process, but Los Banos Municipal Code § 9-3.3005 sets the numbers that apply once a complete application clears review: a detached ADU tops out at sixteen feet and 850 to 1,000 square feet, with just a four-foot side and rear setback, on any residential or mixed-use lot that already has a dwelling.
Accessory dwelling units are allowed in all residential or mixed use or multifamily zoning districts that allow for any single-family or multifamily residential uses where there is a proposed or existing dwelling. ... One detached, new construction, accessory dwelling unit that does not exceed four-foot side and rear yard set-backs for a lot with a proposed or existing single-family dwelling. ... Building Height. Detached accessory dwelling units shall not exceed one story and a height of sixteen (16′) feet, unless the accessory dwelling unit is constructed above a garage, in which case the structure shall comply with the height limits of the underlying zoning district. ... The maximum size of a detached or attached accessory dwelling unit is 850 square feet for a studio or one bedroom unit and 1,000 square feet for a unit with two bedrooms. No more than two bedrooms are allowed.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4356507; v3 updated 2025-03-05).
Full Breakdown
3004. 3001(c); there is no minimum lot area. 3005(c) caps a detached unit at one story and sixteen feet unless it sits above a garage, in which case it follows the underlying district's height limit instead. 3005(d): 850 square feet for a studio or one-bedroom unit, 1,000 square feet for a two-bedroom unit (no more than two bedrooms are allowed), and an attached ADU is further limited to 50% of the existing or proposed primary dwelling's floor area, though the floor-area, open-space or site-coverage standards can never squeeze a unit below 800 square feet.
Detached units combined with an existing multifamily building max out at two units, capped at sixteen feet with the same four-foot setbacks. Every ADU needs a permanent foundation, must match the primary dwelling's architectural style, color and materials, and cannot be sold separately from the lot.
Violations & Fines
An ADU built outside these standards, or without the required building permit and Community Development Director compliance determination under § 9-3.3004, is not a lawful unit; § 9-3.3004(e) lets an illegal ADU be brought into compliance through an application under this article, but it is not validated automatically. Decisions can be appealed under § 9-3.3010.
Frequently Asked Questions
Do I need a use permit for a Los Banos ADU?
How close to my property line can a detached ADU sit?
How big can an ADU be in Los Banos?
Is there a minimum lot size to build an ADU?
Sources & Official References
Other rules in Los Banos
How Los Banos compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Los Banos to another location·View the California accessory structures overview
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