ADUs and Westminster: What the New CO Law Allows

Thinking about adding a backyard cottage or converting your garage in Westminster? You are not alone. Colorado’s new ADU law is opening doors for homeowners who want flexible space for family, rental income, or future resale value. In this guide, you’ll learn what HB24-1152 changes, how Westminster is expected to implement it, and what steps to take if you’re considering an ADU. Let’s dive in.

What HB24-1152 does

HB24-1152 focuses on making accessory dwelling units more attainable across Colorado. In plain terms, the law:

• Requires cities to allow at least one ADU on lots where single-unit homes are allowed.
• Requires administrative, or ministerial, approval for ADU permits using clear, objective standards.
• Limits how cities can require extra parking or owner-occupancy as a condition of approval.

The law still preserves public health and safety protections. You will still need to meet building, fire, and utility standards. Some special districts or overlays may also have additional rules.

What this means in Westminster

Westminster will need to adjust its zoning code and permitting steps so ADUs are allowed by right on qualifying single-unit lots. While final code language will spell out the details, here is what to expect based on the law’s direction and typical city updates.

Where ADUs will be allowed

You should expect one ADU to be permitted on lots where a single-unit home is a listed use. If your property is in a special overlay or historic area, additional standards may apply. Always verify your parcel’s zoning before you plan work.

ADU types likely recognized

Cities usually define ADUs by type so standards are crystal clear:

• Internal or attached ADU within the main home, often a basement or portion of the house with a separate entrance.
• Attached ADU with its own entrance but structurally attached to the primary home.
• Detached ADU, sometimes called a backyard cottage or carriage house, often placed over a garage or as a new small structure.

Westminster’s update should clarify which types are permitted and the standards for each.

Standards the city can still set

Even with ministerial approval, your project must meet objective rules. Expect to see clear standards for:

• Maximum size as a square-foot cap or percentage of the main house.
• Height, setbacks, lot coverage, and privacy/screening.
• Window placement, egress, and fire separation for safety.

These are not subjective design reviews. They are checklist items staff can approve when your plans comply.

Parking and owner occupancy

HB24-1152 limits how cities impose parking and owner-occupancy conditions. Westminster will likely revise or remove blanket extra parking requirements and clarify if any owner-occupancy rules remain. Expect objective criteria and a straightforward pathway if any reductions or waivers apply. The city will publish the final approach in its code.

Permitting and review timeline

Ministerial review means staff must use a clear checklist and make a timely decision without a public hearing. You can expect a defined submittal package, a target review window, and a simple resubmittal or appeal process if your plans need tweaks. Many cities aim for a 2–8 week staff review once a complete application is in.

Fees and utilities

Plan for building permits, inspections, and utility connection considerations. Cities often differentiate between conversions that use existing systems and new detached units that may need new taps or capacity review. Westminster will publish a fee schedule so you can budget accurately.

Steps to take now

Use this simple checklist so you are ready when Westminster’s updates are live:

1. Confirm zoning. Verify that your lot is in a single-unit zone and whether any special overlays apply.
2. Review private covenants. HOAs and deed restrictions may still limit or prohibit ADUs even if the city allows them.
3. Decide your ADU type. Internal conversion, attached addition, or detached cottage each come with different costs and footprints.
4. Sketch a concept. Draft a basic site plan and floor plan so you can test setbacks, height, and access.
5. Talk utilities early. Ask a designer or contractor about plumbing, sewer lateral capacity, electrical load, and potential upgrades.
6. Prepare a budget. Include design, permits, utility work, construction, and contingency.
7. Plan your use. Long-term rental, family use, or office/guest space can guide design and finishes.

Design and code basics

ADUs must meet the same building and safety codes as any dwelling. Typical requirements include:

• A functional kitchen, bathroom, and sleeping area.
• Safe egress, smoke and carbon monoxide detectors, and fire separation between units.
• Proper mechanical, electrical, and plumbing systems sized for two dwellings.

If you are converting a basement or garage, expect upgrades to insulation, ventilation, and egress windows. Detached units must meet setbacks, height, and foundation standards.

Rentals, short-term stays, and HOAs

Westminster will state its policy on short-term rentals separately from ADU rules. Many cities allow ADUs for long-term housing and set specific rules for rentals under a certain number of days. If your property is in an HOA, review the covenants. Private restrictions often remain enforceable even when city zoning allows an ADU.

Budget and timeline signals

Costs vary by project type and site conditions, but you can plan around these common elements:

• Soft costs: design, engineering, and permit fees.
• Utility costs: sewer or water connection adjustments, possible new taps for detached units, and electrical upgrades.
• Construction costs: foundation work, framing, mechanicals, finishes, and site work.

After you submit a complete application, ministerial reviews often target a 2–8 week window, depending on workload. Build time ranges widely, from a few months for a simple internal conversion to many months for a detached cottage.

Buyers, sellers, and ADU value

ADUs can add flexible living options and potential rental income, which many buyers value. Adding an ADU may also change your assessed value and insurance needs. Before you build or buy, check with your insurer and the county assessor on how an ADU could affect taxes and coverage. When you sell, clear permits, high-quality craftsmanship, and documented utility upgrades help buyers feel confident.

Neighborhood fit and good communication

ADUs are a gentle way to add housing without large visual change. Still, some neighbors worry about parking, privacy, or construction impacts. Thoughtful design choices like window placement, fencing, and landscape screening protect privacy. A quick heads-up to neighbors before construction starts can build goodwill.

How Due South Realty can help

If you are weighing an ADU project or shopping for a Westminster home with ADU potential, you deserve clear guidance. Our team understands renovation, staging, and investor math. We help you spot workable lots, estimate timelines, and plan for resale value. When rules are finalized, we will share updates and plain-English checklists so you can move forward with confidence.

Ready to explore your ADU options or find a Westminster property with room to grow? Visit our Lafayette storefront or book a free home consultation with Due South Realty.

Important: Always verify parcel-specific zoning, building requirements, and private covenants with the City of Westminster and your HOA or title documents before you proceed.

FAQs

Can I build an ADU on my Westminster lot?

• If your property is in a zone that allows single-unit homes, HB24-1152 directs cities to allow at least one ADU. Verify your parcel’s zoning and any overlays before you start.

What types of ADUs are likely allowed in Westminster?

• Expect internal conversions, attached ADUs with separate entrances, and detached cottages to be defined. Final rules will specify which types are permitted and their standards.

Will I need to live on site if I add an ADU?

• The law limits how cities can require owner occupancy. Westminster will clarify its final approach in the code. Check the adopted language for specifics.

Is extra off-street parking required for an ADU?

• HB24-1152 limits mandatory parking requirements. Westminster’s update should outline if additional spaces are required, when reductions apply, and any objective criteria.

How long does ministerial review take for an ADU?

• Once your application is complete, many cities target a 2–8 week staff review. Westminster will publish its official timeline and checklist with submittal items.

What fees and utility costs should I expect?

• Plan for permits, inspections, and utility work. Detached units can trigger connection or capacity considerations. The city’s fee schedule will provide exact amounts.

Can I rent my ADU as a short-term rental?

• Short-term rental rules are usually handled separately from ADU approval. Review Westminster’s STR policy to see if permits, limits, or minimum stay rules apply.

Do HOAs or deed restrictions still matter if the city allows ADUs?

• Yes. Private covenants may limit or prohibit ADUs even when zoning permits them. Always review your CC&Rs and consult your HOA.