Milpitas, CA Accessory Structures: ADU Rules (2026)
ADU rules in Milpitas, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Detached ADU max size
- 1,200 sq ft
- Attached ADU max size
- 50% of primary home (min. 800 sq ft allowed)
- Front setback
- Min. 8 ft
- Side/rear setback
- Min. 4 ft
- Height limit
- 16 ft (18 ft near transit, 25 ft if attached)
- Permit type
- Ministerial Building Permit only
- Citation
- § XIII-C.10.030.F
Summary
In the City of Milpitas, an accessory dwelling unit built under Municipal Code § XIII-C.10.030.F is capped at 1,200 square feet if detached, or 50 percent of the primary home's floor area if attached, though an attached ADU may still reach 800 square feet. Front setbacks must be at least eight feet, side and rear setbacks four feet, and height tops out at 16 feet, rising to 18 feet near major transit or 25 feet if attached to the house.
F.Additional ADU Standards.1.Maximum Size.a.Detached ADUs. The total floor area of a detached ADU shall not exceed 1,200 square feet.b.Attached ADUs. The total floor area of an attached ADU shall not exceed 50 percent of the existing primary dwelling; however, this standard shall not prevent an attached ADU from being less than 800 square feet. ... 2.Setbacks.a.Front setbacks shall be a minimum of eight feet unless exempt consistent with C.10.030.F.6 (Other Standards).b.Minimum side and rear setbacks shall be four feet or the setback for the applicable zone, whichever is less. ... 3.Maximum Allowed Height.a.Generally. 16 feet.b.Within ½ mile walking distance of a major transit stop or high-quality transit corridor as defined in California Public Resources Code section 21155. 18 feet.c.Attached to the primary dwelling. 25 feet or the height limitation of the zone, whichever is lower.
Full Breakdown
Beyond the size, setback, and height standards, § XIII-C.10.030 sets the broader ADU framework. A single-family lot may add one attached ADU, one detached ADU, and one JADU; a multi-family lot may add up to eight detached ADUs, capped at the number of existing units, or convert up to 25 percent of existing livable space into ADUs. ADUs and JADUs that meet these standards need only a ministerial Building Permit, reviewed within 60 days, or 30 days when a pre-approved ADU plan is used; an ADU that does not conform instead needs a discretionary Minor Site Development Permit.
No minimum parcel size applies, the smallest allowable unit is a 150-square-foot efficiency unit, and rentals cannot run shorter than 30 days. Height gets an extra two feet if needed to align a roof pitch with the primary structure, and lot coverage, open space, front setback, and floor-area-ratio standards cannot be used to block an 800-square-foot ADU that otherwise meets the height and four-foot side/rear setback minimums. A deed restriction recorded with the Santa Clara County Recorder must be in place before occupancy, confirming the unit cannot be sold separately from the primary dwelling.
Violations & Fines
Building an ADU that exceeds these size, setback, or height limits without first securing the required Minor Site Development Permit is a Title XIII zoning violation. Under § XIII-D.18.040, the responsible party faces a fine of up to $1,000, up to six months in the Santa Clara County jail, or both, with each day of continuing violation treated as a separate offense, and the Building Official may issue a Stop Work Order under § XIII-D.18.060 until the ADU is brought into compliance or a discretionary permit is obtained.
Frequently Asked Questions
How big can a detached ADU be in Milpitas?
What setbacks apply to a Milpitas ADU?
How tall can an ADU be built in Milpitas?
Does my Milpitas ADU need a discretionary permit?
Sources & Official References
Other rules in Milpitas
How Milpitas compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Milpitas to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Santa Clara County handle adu rules.