Accessory Dwelling Unit (ADU) Regulations in Westminster

Max Size- 1,200 sqft or 50% of gross sqft of primary dwelling, whichever is smaller

Max Height- Cannot exceed height of primary dwelling

Westminster now permits ADUs in all single-family residential zones, provided they meet certain criteria:

✔ Only one ADU is allowed per lot.
✔ The ADU must be accessory to a single-family home.
✔ ADUs are not allowed on properties with duplexes, townhomes, or multifamily units.
✔ Mobile homes, RVs, and temporary structures cannot be used as ADUs.
✔ ADUs must be assigned a separate address from the main home.
✔ Detached ADUs must be built on a permanent foundation.

Westminster has specific size limitations and architectural standards to ensure ADUs blend well within existing neighborhoods.

Maximum ADU Size

✔ The ADU cannot exceed 50% of the primary home’s floor area or 1,200 sq/ft, whichever is smaller.
✔ No ADU can have more than two bedrooms.
✔ The minimum ADU size is 190 sq/ft.

Architectural Compatibility

✔ The ADU must maintain the character of the primary residence, including roof pitch, exterior materials, and window design.
✔ Detached ADUs must comply with the same height restrictions as the primary home (maximum 30 feet if built over a garage).

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• HB 24-1152 requires cities to allow ADUs without designated parking, except in these cases:
  ✔ If no parking is currently required for the primary home, parking cannot be required for the ADU.
  ✔ If the lot does not have an existing parking space for the primary home, no additional parking is required.

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✔ ADUs must share water and sewer connections with the primary home—separate meters are not permitted.
✔ All utility bills will be charged to the primary residence’s account holder.

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• HB 24-1152 prohibits cities from requiring owner occupancy meaning ADUs can be rented out separately from the primary home.
• ADUs cannot be sold separately from the main home—they must remain part of the same lot.
• Short-term rentals (STRs) are still prohibited, except in Planned Unit Developments (PUDs) where STRs were previously allowed.

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Under HB 24-1152, all ADU approvals must be handled administratively—meaning there are:
✔ No public hearings
✔ No subjective design reviews
✔ No neighborhood approval required

To build an ADU in Westminster, homeowners must obtain zoning approval and a building permit. The process includes:

1. Pre-Application Consultation – Meet with city planners to discuss zoning compliance.
2. Design Review – Submit site plans and architectural drawings.
3. Building Permit Application – Provide structural details and ensure adherence to Westminster’s ADU design standards.
4. Plan Review & Approval – City officials review all documents to confirm code compliance.
5. Construction & Inspections – The ADU must pass all final inspections before it can be occupied.

Variance Requests:
✔ Homeowners seeking exceptions to size, setbacks, or parking requirements can submit a variance request to Westminster’s Planning Commission.

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Building an ADU in Westminster requires careful planning, compliance with zoning laws, and expert execution—that’s where Kindred Tiny Homes comes in.

✔ We handle everything from design and permitting to construction and final approvals.
✔ We navigate Westminster’s ADU requirements seamlessly, ensuring full compliance.
✔ We create high-quality, beautifully designed ADUs that enhance property value and maximize functionality.

If you’re considering building an ADU in Westminster, contact us today for a free consultation. We'll walk you through your options and help bring your vision to life!

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