How United Build Partners helps Westminster homeowners
We're an ADU advisory and contractor-matching service, not the construction company. We start with a free review of your Westminster property and goals, help you understand the city's multi-division review process, and — when it's a good fit — connect you with up to three contractors in our network experienced with it.
ADU rules and permitting in Westminster
Westminster's ADU rules build on the same statewide floor every California city follows — ministerial review, no discretionary hearings, and a 60-day clock on complete applications (see our California ADU laws guide). What's distinctive about Westminster is how the review itself is organized.
Three divisions, one project
For ADU-only projects, Westminster runs a combined Planning Division zoning clearance alongside a Building Division permit plan check — but a third division, Engineering, also weighs in on applicable requirements. Each division has its own submittal requirements and code provisions to satisfy:
Other standards
- Size: up to 800 square feet for a standard ADU per state minimum standards, with Junior ADUs capped at 500 square feet.
- Height: up to 16 feet for a detached ADU, up to 25 feet if attached to the primary home.
- Fire sprinklers: generally not required in the ADU if they aren't required for the primary residence.
- Application: can be submitted in person or online through the Building Division.
Property and lot considerations
Because Engineering reviews site-specific items like drainage and utility connections separately from Planning and Building, properties with more complex site conditions — grading, drainage patterns, or older utility infrastructure — may see more back-and-forth during review. A property review can help flag these considerations early, before you're deep into design.
Common ADU types for Westminster homeowners
Homeowners with an existing garage often start with a garage conversion, and those with more backyard space look at a detached ADU. A Junior ADU remains the lowest-cost path for converting existing interior space — see our JADU vs. full ADU comparison if you're deciding between the two.
Cost factors in Westminster
Construction costs in Westminster generally track the same $285–$350 per square foot range as the rest of our Orange County service area — see our full ADU cost guide. Coordinating three review divisions doesn't necessarily add construction cost, but it can add design and administrative time that's worth budgeting for.
Financing your Westminster ADU
Most homeowners fund construction through a HELOC, cash-out refinance, or dedicated construction loan — see our ADU financing overview for how each works.
Rental income and property value in Westminster
Rental demand varies by neighborhood in Westminster, and actual achievable rent depends heavily on your specific unit and location — we don't have a verified, current rent figure to quote. See our ADU rental income guide and ROI calculator to work through your own numbers.
How our process works
Frequently asked questions
Planning, Building, and Engineering each review different aspects of your project — zoning and design, structural and life-safety code compliance, and site-specific items like drainage and utilities, respectively. A contractor experienced with Westminster's process can help coordinate all three.
Generally not, if fire sprinklers aren't already required for your primary residence. Confirm your property's specific requirement with the Building Division.
Yes — Westminster accepts ADU applications in person or online through the Building Division.