San Bernardino County

Barstow ADU rules

Research summary of what we found for City of Barstow in San Bernardino County. Not a determination for a specific lot.

Last checked November 3, 2026.

City or county ADU page

Barstow Planning department. No ADU-specific page was found.

How big can an ADU be in Barstow?

Maximum size
An ADU may be up to 1,200 sq ft or 75% of the main home's existing living area, whichever is less, and at least 150 sq ft. Under state law the 75% cap cannot bring the limit below 850 sq ft (one bedroom or less) or 1,000 sq ft (more bedrooms), and an 800 sq ft detached ADU with 4 ft side and rear setbacks is allowed in every case. A JADU may be up to 500 sq ft.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(3), accessed 2026-11-03.

ADU setbacks in Barstow

Setbacks
ADUs need 4 ft side and rear setbacks and must follow the zone's front setback. In planned unit districts, the yards in the district's final development plan apply, but side and rear setbacks for an ADU are no more than 4 ft.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(1), (f)(2)(b), accessed 2026-11-03.

What we found for Barstow

What we have for this place. Where a local figure is stricter than the California state baseline, both are shown.

Local ADU rules
Barstow's ADU rules are in Municipal Code Section 19.10.070, last amended by Ordinance 976-2021 (August 16, 2021). An ADU that meets the section is acted on ministerially, without a hearing, within 60 days of a complete application, and needs a building permit. Some parts no longer match state ADU law, so this page shows only the parts that do. Confirm the current rules with the City's Planning Division.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(c), (e), accessed 2026-11-03.

Height
An ADU may be up to 16 ft tall. Existing legal structures converted to an ADU may keep their height. State law also allows 18 ft (plus 2 ft for a matching roof pitch) within a half mile walk of a major transit stop or high-quality transit corridor, and an attached ADU up to 25 ft or the zone limit, whichever is lower.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(5), accessed 2026-11-03.

Parking
A lot with an ADU needs one more paved off-street space than the main home needs. Parking is not allowed in front-yard landscaped areas. No space is needed within a half mile walk of public transit, in a historic district, for an ADU that is part of the existing home or an existing accessory structure, where on-street permits are required but not offered, or within one block of a car share vehicle. JADUs need no parking.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(8), accessed 2026-11-03.

Junior ADUs
A JADU may be up to 500 sq ft and needs no parking.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(3)(a), (f)(8), accessed 2026-11-03.

Design and entry
An ADU must use the same exterior design, building and roof materials, and colors as the main home, and needs a permanent foundation. Its entrance must be on the side or rear and not visible from the street. Modular homes may be used; manufactured homes need City review; mobile homes, RVs and trailers may not be used.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(7), (9)-(11), accessed 2026-11-03.

Fees, utilities and rentals
No development impact fees for ADUs under 750 sq ft; larger ADUs pay fees in proportion to their size. An ADU not built with a new home needs no new separate utility connection or connection fee, though a detached ADU may need a separate connection or meter. Units may not be rented for less than 31 days, and an ADU may not be sold separately from the main home.
Source: Barstow Municipal Code § 19.10.070 Accessory dwelling units and junior accessory dwelling units (Municode), § 19.10.070(f)(12)(c), (g), (j), (k), accessed 2026-11-03.

State housing department (HCD) review
On February 27, 2026, HCD wrote that the most recent Barstow ADU ordinance on file is from 2021 and may be out of date and out of compliance with state ADU law. It listed the state law changes since then, including bans on ADU deed restrictions and ADU owner occupancy and the narrower JADU owner occupancy rule, and asked the City to respond by March 29, 2026. Confirm the current rules with the City of Barstow.
Source: HCD ordinance review letter, City of Barstow (technical assistance), Letter of February 27, 2026, accessed 2026-11-03.

California state rules

The statewide baseline recorded from state law and the HCD ADU Handbook.

Detached size cap described in state law
1,200 sq ft. From Government Code section 66314.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.

Side and rear setback cap for a new ADU
4 ft. From Government Code section 66314, which describes a cap on side and rear setbacks for a new ADU.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.

Setback for a conversion of an existing structure
No additional setback, from Government Code section 66314 for a conversion of an existing structure.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.

Minimum lot size
A city may not impose a minimum lot size for an ADU, from Government Code section 66314.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.

Minimum unit the handbook says cities must allow
At least an 800 sq ft ADU with 4 ft side and rear setbacks. The HCD ADU Handbook (updated March 2026) describes this under section 66321(b)(3).
Source: HCD ADU Handbook, 66321(b)(3); handbook updated March 2026, accessed 2026-10-16.

Detached height described in the handbook
16 ft, or 18 ft or 20 ft in some cases. The HCD ADU Handbook (updated March 2026) describes this under section 66321(b)(4).
Source: HCD ADU Handbook, 66321(b)(4); handbook updated March 2026, accessed 2026-10-16.

Permit decision deadline
60 days. From Government Code section 66317(a)(3): the permitting agency must decide on (approve or deny) a completed ADU application within 60 days when an existing single-family or multifamily dwelling is on the lot. Section 66317(a)(1) says the application is considered ministerially, without discretionary review or a hearing.
Source: California Government Code section 66317, 66317(a)(1), (a)(3), accessed 2026-10-17.

Owner-occupancy requirement
None. From Government Code section 66315: a local agency may not impose an owner-occupancy requirement on an ADU. It may require that the property be used for rentals of terms 30 days or longer. The HCD ADU Handbook (updated March 2026) describes the same rule.
Source: California Government Code section 66315, 66315; HCD ADU Handbook updated March 2026, accessed 2026-10-17.

Parking near public transit
No parking standards within one-half mile walking distance of public transit. From Government Code section 66322(a)(1). Section 66322(a) lists several other cases where parking standards may not be imposed.
Source: California Government Code section 66322, 66322(a), accessed 2026-10-17.

Ministerial categories
The HCD ADU Handbook (updated March 2026) states that Government Code section 66323 sets four ministerial categories. What we have does not restate those four categories.
Source: HCD ADU Handbook, 66323; handbook updated March 2026, accessed 2026-10-16.

Fire Hazard Severity Zones
If your lot is in a Fire Hazard Severity Zone, the CAL FIRE Office of the State Fire Marshal says in Information Bulletin 25-004 (issued March 3, 2025): “Fire Hazard Severity Zones (FHSZs) should not restrict the development of Accessory Dwelling Units (ADUs). However, additional building standards may be necessary, including but not limited to California Fire Code Chapter 49 and California Building Code Chapter 7A.” State ADU law does not itself bar an ADU there. A city or county may still apply its building code, including wildfire-resistant construction (Gov. Code 66314(d)(8)); require side and rear setbacks “sufficient for fire and safety” for a unit converted under 66323(a)(1); and decline parking in setbacks on specific fire and life safety findings (66314(d)(10)(B)). It may also consider public safety when it designates where ADUs may be permitted (66314(a)). Sprinklers can't be required in an ADU or JADU if the primary residence doesn't need them (66314(d)(12), 66323(d)). Some cities and counties still apply their own fire-zone limits. Where this summary has one, it is listed with the local rules. This summary does not look up your lot. Check the CAL FIRE Fire Hazard Severity Zone map viewer linked from the State Fire Marshal's Fire Hazard Severity Zones page: https://experience.arcgis.com/experience/5065c998b4b0462f9ec3c6c226c610a9
Source: CAL FIRE Office of the State Fire Marshal Information Bulletin 25-004, page 4, issued March 3, 2025; Gov. Code 66314, 66323, accessed 2026-10-20.

State baseline on the directory → · State ADU rules on the homepage →

Can I build an ADU in Barstow?

State law sets a baseline for ADUs in Barstow, and what we found locally is listed on this page. Whether a specific lot can add an ADU depends on zoning, utilities, and other site facts this page does not measure. Confirm with the City of Barstow Community Development Department (Planning), or run a free address summary.

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