Santa Clara County

Milpitas ADU rules

Research summary of what we found for City of Milpitas in Santa Clara County. Not a determination for a specific lot.

Last checked November 3, 2026.

City or county ADU page

How big can an ADU be in Milpitas?

Maximum size
A detached ADU may be up to 1,200 sq ft. An attached ADU may be up to 50% of the existing main home, but that limit cannot hold an attached ADU below 800 sq ft. An ADU made from existing space may be larger, and up to 150 sq ft may be added to a converted accessory structure for entry and exit. The smallest ADU or JADU is 150 sq ft. Lot coverage, open space, front setback, floor area and design rules cannot block an ADU of up to 800 sq ft with 4 ft side and rear setbacks.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(E)(4), (F)(1), (F)(6), accessed 2026-11-03.

ADU setbacks in Milpitas

Setbacks
New ADUs need side and rear setbacks of 4 ft, or the zone's setback if that is smaller. The front setback is 8 ft, but it cannot block an ADU of up to 800 sq ft. A detached ADU rebuilt in the same place and size as an existing structure may keep that structure's setbacks. A new detached ADU must sit behind the street-facing front of the main home, where state law allows that rule.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(F)(2), (F)(5)(a), (F)(6), accessed 2026-11-03.

What we found for Milpitas

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

Local ADU rules
Milpitas's ADU rules are in Zoning Ordinance Section XIII-C.10.030 (Title XIII of the Municipal Code), part of the new Comprehensive Zoning Ordinance adopted September 2, 2025 and in effect October 2, 2025. An ADU or JADU that meets these standards needs only a building permit, reviewed without a hearing. The City acts within 60 days of a complete application, or 30 days when a ready-made ADU plan is used. An ADU that does not meet the standards may be allowed with a Minor Site Development Permit.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(B), (D)(1)-(2), accessed 2026-11-03.

Number of ADUs
On a lot with a single-family home: one attached ADU, one detached ADU and one JADU. On a lot with an existing multifamily building: up to eight detached ADUs (not more than the number of existing units), plus ADUs converted from non-livable space up to 25% of the units. On a lot with a proposed multifamily building: up to two detached ADUs. No minimum lot size applies.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(C), (E)(3), accessed 2026-11-03.

Height
An ADU may be 16 ft. It may be 18 ft within a half mile walk of a major transit stop or high-quality transit corridor, or on a lot with an existing or proposed multistory multifamily building. An attached ADU may be 25 ft or the zone's height limit, whichever is lower. Any ADU may add 2 ft for a roof pitch that matches the main home.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(F)(3), accessed 2026-11-03.

Parking
One off-street space per ADU. It may be tandem and may be in setbacks, but not in the front yard unless on the driveway. No space is needed within a half mile walk of public transit, in a historic district, for an ADU inside the home or an existing accessory structure, where on-street permits are required but not offered, within one block of a car share stop, or when the ADU is filed with a new home or multifamily building. Garage, carport or uncovered spaces removed or converted for an ADU do not have to be replaced. JADUs need no parking.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(F)(4), (G)(3), accessed 2026-11-03.

Design
These apply only as far as state law allows. A converted garage must replace the garage door with windows or a door (not a street-facing door for an attached ADU). Within 10 ft of a side or rear property line, a 6 ft solid fence or plants that grow at least 10 ft tall are needed. Exterior materials and colors must match the main home. An attached ADU may not have an inside connection to the main home. ADUs and JADUs on single-family lots also follow the City's single-family design standards unless state law bars them.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(E)(5), (F)(5)(b)-(d), (F)(8), accessed 2026-11-03.

Junior ADUs
A JADU needs an entrance separate from the home's main entrance. If it has no bathroom of its own, it needs an inside door to the main living area. No parking is needed. The City's ADU page says that, under AB 1154, the owner must live in the home only when the JADU shares a bathroom with it. A JADU deed restriction form from the City is recorded with the County.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(G)(2)-(3), accessed 2026-11-03.

Fees, utilities, sprinklers and renting
No impact fees for a JADU or an ADU under 750 sq ft; larger ADUs pay in proportion to the main home's size. An ADU or JADU inside an existing structure needs no new utility connection. Other ADUs need a new or separate connection, with charges based on size or plumbing fixtures. Fire sprinklers are needed only if the main home needs them. ADUs and JADUs may be rented for 30 days or more but not sold separately, except by a qualified nonprofit under Gov. Code § 66341. No ADU has an owner occupancy rule.
Source: Milpitas Comprehensive Zoning Ordinance (Title XIII), § XIII-C.10.030 Accessory Dwelling Units and Junior Accessory Dwelling Units (City of Milpitas, adopted text), § XIII-C.10.030(D)(3), (E)(1)-(2), (E)(6), (F)(7), accessed 2026-11-03.

ADU help
The City offers online "ADU Monday" meetings with Building Safety, Planning and Land Development staff, an ADU Toolkit (which the City says may be partly out of date) and an ADU permit fee guide. The Office of Building Safety runs a fee incentive program, a program to legalize existing ADUs, and ready-made ADU plans. Questions: adu@milpitas.gov or Planning at 408-586-3279.
Source: City of Milpitas, Accessory Dwelling Units (ADUs), Page text, 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.

Starting January 1, 2027: two detached ADUs
Starting January 1, 2027, AB 956 (Chapter 791, Statutes of 2026) raises from one to two the number of new detached ADUs a city or county must allow, without discretionary review, on a lot with a proposed or existing single-family home (Gov. Code 66323(a)). Each may be held to 800 sq ft, 4 ft side and rear setbacks and the state height limits. The city or county does not have to also allow a JADU on a lot where two new detached ADUs have been built. AB 956 also makes HOA and deed rules that effectively prohibit or unreasonably restrict an ADU or JADU void on any lot zoned to allow a single-family home, not only lots zoned for single-family use (Civil Code 4751 and 714.3).
Source: AB 956 (2025-2026), Chapter 791, Statutes of 2026, Gov. Code 66323; Civil Code 714.3, 4751; signed September 29, 2026, accessed 2026-11-03.

Starting January 1, 2027: impact fees above 750 sq ft
No impact fee may be charged on an ADU of 750 sq ft or less, or a JADU of 500 sq ft or less (Gov. Code 66311.5(c)). Starting January 1, 2027, SB 1117 (Chapter 809, Statutes of 2026) changes how fees are figured for larger ADUs: for up to two ADUs on a lot, the proportional impact fee is charged only on the interior livable space above 750 sq ft. On a lot with more than two ADUs, the fee stays proportional to the whole ADU. Utility connection fees and capacity charges are not changed.
Source: SB 1117 (2025-2026), Chapter 809, Statutes of 2026, Gov. Code 66311.5(c); signed September 29, 2026, accessed 2026-11-03.

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

ADU rules near Milpitas

Fremont · about 5 miles
Santa Clara · about 6 miles
Sunnyvale · about 8 miles
Newark · about 9 miles
San José · about 10 miles

Can I build an ADU in Milpitas?

State law sets a baseline for ADUs in Milpitas, 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 Milpitas Planning Department, or run a free address summary.

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