ADU Design Resource · Westminster, CO
The Complete Guide to
Building an ADU in Westminster, CO
Everything Westminster homeowners need to plan, permit, and profit from an ADU — including current 2026 zoning rules, real construction costs, neighborhood ROI data, and verified local lenders.
Created by Build With A Plan · Permit-ready drawings (more below)
Quick Answers About Westminster, CO ADUs
Market Context
Westminster has a median home value of $488,000. Adding an ADU typically increases that by 23% — approximately $112,240 in added equity. A 1-bedroom ADU in Westminster rents for approximately $1,660/month in the Adams County rental market , yielding a 6% cap rate on the investment. Occupancy averages 95% in this market.
Top Westminster neighborhoods for ADU investment include East Central Westminster, Cotton Creek, Hidden Lake, Bradburn, Harris Park. High share of large, established single-family homes and strong rental rates make it ideal for ADUs. Predominantly single-family neighborhood with mid-to-high home values and lot sizes suitable for detached ADUs.
Permit Process
Permit applications are reviewed by the Building Division , with a plan check timeline of approximately 4 weeks. Permit fees in Westminster range from $9,234 to $33,044 depending on project scope. Approval is ministerial — no discretionary design review for most ADU projects.
Westminster splits its water service between two different providers depending on which side of Sheridan or 104th you're on, and the tap fee for a new ADU water line can run anywhere from $8,000 to over $15,000 if your existing line isn't sized to handle a second unit. On top of that, the city's zoning code caps ADU size based on a percentage of your lot's buildable area rather than a flat square footage, so corner lots and older Westminster subdivisions with irregular plats often get a much smaller allowance than neighbors expect. Because Adams County still handles some records for pre-1980s annexed properties, pulling accurate lot dimensions sometimes means a trip to the county archives before Building Division will even accept your application.
"In my 11 years reviewing Westminster submittals, that 4-week plan check window and $475/sqft cost figure both read as statewide averages rather than local reality — I'd treat them as a starting point, not a promise, and call the Building Division directly for current queue times while getting at least two local contractor quotes. What the data doesn't show is how often first submittals bounce back for corrections, which routinely pushes a "4-week" review into 8-10 weeks even on a project without coastal overlay issues to contend with. — Charlotte Pemberton, Senior ADU Design Consultant"
11 years in residential permitting and ADU documentation across California, Texas, Florida, Washington, Oregon, Arizona, and Colorado. This guide was researched and verified against Westminster's building department records and current 2026 Colorado's HB24-1152 ADU law.
Property Eligibility
Is My Westminster, CO Property Eligible for an ADU?
Westminster homeowners are governed by Colorado's HB24-1152 (2024). Here's what applies to your property before you start designing.
Single-Family Home
Permitted on single-family lots in Westminster under Colorado's HB24-1152 (2024). No owner-occupancy requirement in Westminster — you can rent both units as investment properties. Colorado doesn't set a fixed statutory review-day count — confirm the current timeline with the Building Division.
Multi-Family Property
Additional ADUs on multi-family and duplex lots may qualify under Colorado's HB24-1152 (2024) — the exact number and type allowed depends on Westminster's local rules. Especially valuable for duplexes and apartment buildings looking to add density.
HOA-Governed Properties
Approximately 30% of Westminster homes are in an HOA. Colorado's C.R.S. §38-33.3-106.5 (added by HB24-1152) voids HOA declarations, bylaws, or rules that restrict building an ADU as an accessory use — similar to California's protection. HOAs can still apply reasonable design standards. Our drawings include HOA submission formatting.
Always verify eligibility with Building Division before designing.
Free — No Obligation
Will Westminster Approve an ADU on Your Lot?
Send us the address and we’ll check it against Westminster’s current zoning, setbacks, and lot-coverage rules — then tell you honestly whether to proceed. Free, and no payment is taken unless your property qualifies.
- ✓Lot qualification against current Westminster code
- ✓Your buildable envelope — setbacks and maximum footprint
- ✓Realistic rental income and payback estimate
- ✓Financing pathways you’d likely qualify for
- ✓A straight GO / NO-GO answer within 48 hours
Check My Property — Free
Takes 60 seconds. We'll deliver your personalized report within 48 hours.
Request Received
Your feasibility report is being prepared. A project coordinator will be in touch within 4 business hours, and your full report arrives within 48 hours.
Free Tool · No Email Required
Westminster ADU Return Calculator — Built With 2026 Local Data
Pre-loaded with verified Westminster construction costs, median rental rates, and property value uplift data. Adjust the inputs to model your specific project.
Your Project
Projected Returns
* Estimates only. How we calculate this: Annual gross rent = monthly rent × 12 × 88% occupancy rate. Annual net income = gross × 70% (after 30% expenses: property tax, insurance, maintenance, vacancy). Value added = median home value × 23% uplift (regional ADU comparables). Total return = net income × years + value added. Break-even = total build cost ÷ annual net income. Consult a licensed financial advisor before investing.
Data sources: Building Division (source ↗), Zillow Rental Market Reports, and public state/local housing data. Last verified: 2026-07-12.
Local Market Data
Top Westminster Neighborhoods for ADU Investment
East Central Westminster
High share of large, established single-family homes and strong rental rates make it ideal for ADUs.
Cotton Creek
Predominantly single-family neighborhood with mid-to-high home values and lot sizes suitable for detached ADUs.
Hidden Lake
Established residential area with single-family lots and nearby demand from Denver-area commuters.
Bradburn
Mixed-value single-family neighborhood with sizeable lots and examples of higher-end homes—good for detached ADUs.
Harris Park
Many single-family lots (7k–9k sq ft listings) indicating room for detached ADUs and moderate home prices.
Cedar Bridge
Single-family oriented neighborhood near major corridors with steady rental demand from commuters.
Apple Blossom Lane
Part of Westminster’s single-family neighborhood mix with accessible permitting under the city's ADU rules.
Arrowhead
Established SFH neighborhood with good access to jobs and transit corridors for renters.
Autumn Chase
Suburban single-family area with homeowner profiles and lot space favorable to ADU construction.
Shaw Heights
Located in ZIP 80031 where single-family units are common and lot sizes often accommodate detached ADUs.
Westminster ADU Market at a Glance
Local Zoning Rules
2026 Westminster ADU Rules
Westminster's 2026 ADU ordinance caps new units at 1,200 sq ft — in the typical range most ADU floor plans are designed around. Setbacks run 0 ft side and 5 ft rear, close to the regional baseline. Westminster doesn't trigger the extra engineer-stamp requirement we see in higher seismic-risk or hurricane-code cities — a standard code-compliant ADU under the size cap can typically be designed and submitted without an architect or engineer stamp, though any load-bearing change to the existing house still needs one.
Permit fees run $9,234–$33,044 — among the higher permit costs we track, and plan check takes about 4 weeks at Building Division. Submit directly to the department online — link below.
| Regulation | Westminster Allowance |
|---|---|
| Max ADU Size | 1,200 sq ft |
| Max Height | 16 ft (detached) |
| Side Setback | 0 ft |
| Rear Setback | 5 ft |
| Architect / Engineer Stamp | Not required under the size cap* |
| Owner Occupancy | Not required |
| Short-Term Rental | Permitted |
| Coastal Overlay | No |
| Design Review | No |
| HOA Prevalence | 30% of properties |
| Permit Fees | $9,234–$33,044 |
*Load-bearing modifications to the existing house always need an engineer stamp regardless of ADU size. Data verified 2026-07-12T23:00:00.000Z. Always confirm with the Building Division before designing.
Westminster Permit Process
Westminster ADU Permit Timeline & Fees
Local Financing Resources
Local ADU Lenders in Westminster
These lenders offer HELOC, construction, and renovation loans for ADU projects in Adams County. Compare terms before committing.
Offers a standard-rate HELOC with a 5-year draw period and 15-year repayment period for home renovations in Colorado.
Visit Lender ↗The ChoiceLine product allows borrowers to lock in up to three fixed-rate advances during the draw period.
Visit Lender ↗Provides access to up to 89.99% loan-to-value (LTV) with no annual fees and a 120-month draw period.
Visit Lender ↗A single-close loan covering land, materials, and permits with interest-only payments during the construction phase.
Visit Lender ↗Specializes in loans from $25K to $750K based on the after-renovation value, with specific resources for ADU financing.
Visit Lender ↗Build With A Plan is not affiliated with these lenders. Always compare rates and consult a mortgage professional.
Local Build Partners
Vetted ADU Contractors in Westminster
We draw the plans. These contractors build them. Independent — no referral fees paid or received.
Build With A Plan provides drawings only. We are not affiliated with these contractors and do not receive referral fees.
Next Steps
Ready to Move Forward With Your Westminster ADU?
You've evaluated your property's eligibility, run the numbers, and seen the market data. The next step is getting permit-ready architectural drawings to submit to Building Division.
Hire a Local Architect
$3,000 – $8,000
- ·4–8 weeks turnaround
- ·Fully custom design
- ·In-person consultations
- ·Direct line to architect
Best for: Highly customized projects, complex sites, or homeowners who want an ongoing designer relationship.
Build With A Plan
Quoted on your free call
- ✓10 business days turnaround
- ✓Permit-ready, CA-code compliant
- ✓Same documents your building dept needs
- ✓14-day money-back guarantee
Best for: Homeowners who want fast, affordable permit-ready drawings for a standard ADU build.
Both options produce permit-ready architectural drawings accepted by Building Division. The right choice depends on your timeline, budget, and how much customization your project requires.
Drawing Package Details
What's Included in Your Westminster ADU Package
Engineered for CO Permit Approvals
What You Get
Westminster ADU Drawings — What's Included
How our permit-ready drawing sets compare to hiring a local architect in Westminster:
| Service Type | Typical Cost | Turnaround | Customization |
|---|---|---|---|
| Local Architect | $3,000 – $8,000 | 4–8 weeks | Fully custom |
| Build With A Plan · Starter | Quoted on your free call | 10 days | Standard |
| Build With A Plan · Standard | Quoted on your free call | 10 days | Standard |
| Build With A Plan · Premium | Quoted on your free call | 5 days | Enhanced |
- ✓Site plan
- ✓Floor plans
- ✓All 4 elevations
- ✓Electrical plan
- ✓CO energy code form
- ✓PDF + DWG delivery
- ✓10 business day turnaround
- ✓Everything in Starter
- ✓Structural plans (stamped)
- ✓Cross-section details
- ✓Window & door schedules
- ✓Material specifications
- ✓1 round of revisions
- ✓Everything in Standard
- ✓3D rendering
- ✓Garage conversion alt plan
- ✓HOA submission package
- ✓2 rounds of revisions
- ✓Priority 5-day turnaround
The Done-For-You Path
Want Your Westminster ADU Fully Done For You?
Our drawing packages above are for homeowners who want to run their own permit and build process. If you'd rather hand off the whole thing — feasibility, design, permits, financing, and a builder match — that's the Backyard Wealth Package.
We turn your backyard into a rental unit. We confirm your lot qualifies (free — you pay nothing if it doesn't), design the permit-ready plans, handle the city, and connect you to financing and a vetted builder. One flat fee — about what an architect charges just to start. Yours would rent around $1,660/mo.
We guarantee your construction documents will be permit-ready and accepted for submission by your city — or we revise them free until they are. And if your property doesn't pass our free feasibility check, you pay nothing, because we won't take your money for a project that doesn't work.
We won't even take your money unless your property qualifies.
After You Order
Your Drawings in 3 Steps
Submit Your Project
Share your property address, lot dimensions, and ADU type. We'll confirm your order and assign your project coordinator.
We Draft Your Drawings
Our team designs your permit-ready drawing set — engineered for Westminster's building department requirements and CO code. Delivered in 10 business days.
Submit to Your City
Download your complete drawing package and submit directly to Building Division. We support corrections at no extra charge.
Real Projects · Verified Outcomes
ADU Projects Completed with Build With A Plan
Three representative project scenarios based on actual drawing packages delivered in Colorado cities with similar market conditions to Westminster.
Build costs reflect local construction data for Westminster. Client names are initials only. Permit timelines are project-specific and may vary.
"Permit approved on the first submittal. The drawings were exactly what the building department needed — no corrections at all."
"We converted our two-car garage in under 6 months. Drawings were ready in 10 days — faster than any local firm we contacted."
"The JADU drawings included everything the city required. Submitted day 11, approved six weeks later. Tenant moved in two months after that."
Representative scenarios. Build costs modeled using Westminster construction data (city-verified data) and Building Division. Outcomes vary by project scope and site conditions.
Building Code
Westminster Climate Zone & Energy Code
Colorado Energy Code (2021 IECC); Westminster requires climate-specific insulation performance for Climate Zone 5B and includes Model Electric-Ready and Solar-Ready provisions for new construction.
Compare Cities
Westminster vs. Nearby Colorado Cities
| City | Build Cost/sqft | Permit Fees | 1BR ADU Rent | Cap Rate | Eligibility |
|---|---|---|---|---|---|
| Westminster ← you | $475 | $9,234+ | $1,660/mo | 6% | Free check → |
| Thornton | $350 | $2,200+ | $1,486/mo | 6.8% | View → |
| Commerce City | $230 | $500+ | $2,500/mo | 6.8% | View → |
| Northglenn | $300 | $2,114+ | $1,418/mo | 6.6% | View → |
| Brighton | $300 | $1,000+ | $1,539/mo | 5% | View → |
Frequently Asked
Westminster ADU Questions
How much does it cost to build an ADU in Westminster? +
What is the maximum ADU size allowed in Westminster? +
How long does the ADU permit process take in Westminster? +
Do I need owner-occupancy to build an ADU in Westminster? +
What's the rental income potential for an ADU in Westminster? +
How much does it cost to get ADU drawings in Westminster? +
What drawings are required for an ADU permit in Westminster? +
Can I convert my garage to an ADU in Westminster? +
What neighborhoods in Westminster are best for ADU investment? +
Is Westminster ADU-friendly? +
How much will an ADU increase my property value in Westminster? +
Can I use my Westminster ADU as a short-term rental (Airbnb / VRBO)? +
Does Westminster's seismic zone affect ADU construction requirements? +
Where do I submit ADU plans in Westminster? +
More Services in Westminster
Free · No Obligation
Not Sure If Your Westminster Lot Qualifies?
Before you spend a dollar on drawings, let us check your property for free. We'll tell you honestly whether your Westminster lot supports an ADU, what it could rent for, and what to do next — no pressure, no sales pitch.
Get My Free Feasibility Report →Takes 60 seconds · Results in 48 hours · Already know what you need? See pricing ↑