Milpitas regulates ADUs under Zoning Ordinance §XIII-C.10.030. Compliant ADUs need only a building permit, the City acts within 60 days of a complete application — 30 days with a pre-approved plan — and flood zones and the hillside area shape what's possible on many lots.
Facts verified 2026-10-09 against official City of Milpitas sources · see Sources below
Lot Eligibility
Milpitas allows ADUs on single-family and multi-family lots with no minimum parcel size. A single-family lot can have one attached ADU, one detached ADU and one JADU. Rules as of 2026-10-09.
Instant eligibility check — Milpitas rules as of 2026-10-09
No minimum parcel size applies, and ADUs need at least 150 sq ft. Detached ADUs must sit behind the street-facing façade of the main home.
The code asks for one space per ADU, but lots within a half-mile walk of public transit, ADUs inside the existing home or an accessory structure, and several other cases are exempt. JADUs need no parking.
The City notes a large portion of Milpitas is in the FEMA Special Flood Hazard Area, and the Hillside Building Code area lies east of North Park Victoria, Evans Road and Piedmont Road. Both affect pre-approved plan eligibility.
ADU Types & Sizes
Milpitas sets fixed caps: 1,200 sq ft for detached ADUs and 50% of the main home for attached ADUs, with an 800 sq ft allowance guaranteed even where lot coverage, FAR or open-space rules would otherwise block it.
| Rule | Milpitas | Source |
|---|---|---|
| Detached ADU maximum | 1,200 sq ft | MZO §C.10.030.F.1 |
| Detached height | 16 ft; 18 ft near major transit | MZO §C.10.030.F.3 |
| Front setback | 8 ft minimum | MZO §C.10.030.F.2 |
| Side & rear setback | 4 ft (or zone, if less) | MZO §C.10.030.F.2 |
| Parking | 1 space per ADU, many exemptions | MZO §C.10.030.F.4 |
| Impact fees | None for JADU or ADU <750 sq ft | MZO §C.10.030.D.3 |
| Owner occupancy (ADU) | Not required | MZO §C.10.030.F.7 |
| Minimum rental term | 30 days | MZO §C.10.030.E.2 |
Permit Process
Compliant ADUs and JADUs need a building permit only. Milpitas offers free virtual ADU Monday appointments with Building Safety, Planning and Land Development, and a Pre-Approved ADU Program for detached units that can cut plan review turnaround by as much as 50%.
#1: Flood zone (SFHA) lots
Pre-approved plans don't qualify in the Special Flood Hazard Area unless they include a flood-resistant design option. Check your parcel's flood zone in the City GIS before choosing a plan.
#2: Pre-approved plans over 800 sq ft
A Minor Site Development Permit from Planning is required before the building permit, and any modification to a pre-approved plan disqualifies it from the program.
Parcel Check
Look up your parcel in the City GIS for zoning, flood zone and Hillside Building Code status, and check for easements — detached ADUs can't be built within an easement.
Hillside Building Code lots (east of North Park Victoria, Evans Road and Piedmont Road) don't qualify for pre-approved plans.
Book an ADU Monday
Schedule a free virtual meeting with City staff, or email adu@milpitas.gov. Planning: 408-586-3279.
Custom or Pre-Approved Plan
Choose a pre-approved detached plan (no modifications allowed, site-specific plans still required) or a custom design fitted to your lot. zHeight prepares custom permit sets and the site-specific sheets either path needs.
Submit Online
Submit the building permit application online through the City's e-Permits system. Building Permit Center: (408) 586-3240.
City Review
Milpitas acts within 60 days of a complete application, or 30 days for a pre-approved plan; resubmittals after a notice of deficiency follow the same clock. zHeight answers every correction letter.
Fees, Deed Restriction, Permit
Pay permit and any utility connection fees, record the ADU/JADU deed restriction with the Santa Clara County recorder before occupancy, and hire a licensed California general contractor to build.
Cost Guide
Milpitas publishes an ADU Permit Fee Estimate based on its FY25-26 fee schedule. Construction pricing isn't government data, so we don't list a range.
From $7,999
zHeight flat-fee 749 sq ft ADU permit set ($7,999) or JADU garage conversion set ($4,888); custom projects quoted individually.
$4,852.84+
City estimate (minimum) for a 700 sq ft ADU. 500 sq ft: $4,048.31+; 800 sq ft: $5,255.11+; 1,200 sq ft: $6,930.75+. Final fees may vary.
Contractor bid
Paid to your licensed general contractor, not zHeight. Not an official figure.
Verify Permit Fees Before Budgeting
From the City's ADU Permit Fee Estimate: a new address request is $709; Fire Department review of $703 may apply where sprinklers are required; projects adding more than 500 sq ft pay the School Impact Fee; there is no park in-lieu fee. When new utility connections are required on a single-family lot, water ($1,910), sewer ($1,908) and treatment plant ($880) fees are each scaled by ADU area ÷ main-home area. Under §XIII-C.10.030.D.3, no impact fees apply to JADUs or ADUs under 750 sq ft.
Want a cost estimate for your specific lot and ADU type?
Get a Free Project EstimateWhy zHeight
In Milpitas, the parcel itself often decides the path: flood zone, hillside area, transit distance for parking, and whether you stay under 800 sq ft for pre-approved plans.
Before design: zHeight checks flood-zone and hillside status, whether your lot is parking-exempt, and whether a pre-approved plan or a custom design is faster for your site — then prepares the full permit set and handles City corrections.
| What you need | DIY / Generic | zHeight Package |
|---|---|---|
| Flood & hillside check | Discovered after a plan is chosen | Confirmed in GIS before design starts |
| Parking | Space added that may not be required | Exemptions checked against §C.10.030.F.4 |
| Design standards | Colors, fencing, façade rules missed | Matching materials, screening and placement drawn in |
| Title 24 CF1R | Ordered separately | Included in every permit set |
| Plan check corrections | You answer the City's comments | zHeight responds until the permit is issued |
Incomplete plan sets are a common reason applications bounce at intake. zHeight prepares an organized, complete submission — all required sheets, structural calculations and Title 24 CF1R included.
zHeight provides design drawings, structural engineering, Title 24 compliance and permit processing. After your permit is issued, you hire a licensed California general contractor; we answer plan questions and handle permit revisions.
FAQ
Have a question not answered here?
Our team typically responds within one business day.
zHeight — Milpitas
We prepare the complete permit package — design drawings, structural, Title 24 CF1R and correction responses — after checking your parcel's flood, hillside and parking status.
Sources & last verified (2026-10-09)
Rules change — confirm current requirements and fees with the City of Milpitas before designing or budgeting. zHeight is not affiliated with the City.