ADUs are allowed in WestminsterTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Westminster, CO
Is your property eligible for an ADU?
# of Properties
37,011
Owner-occupied
81%
Zoning districts
44
Avg Home Value
$665,013
Median Lot Size
0.16 acres
Avg Income
$117,124
Residential Types:
37,011 housing units
Single Family
8%
2-3 Family
1%
Apts (4+ units)
3%
Other
89%
Zoning Districts:
42,622 parcels · 44 districts
PUD
77%(32,769)
R-1
7%(3,059)
R-A
5%(1,947)
R-1-C
3%(1,485)
Other
8%(3,362)
ADU Rules
What can you build in Westminster, CO?
Westminster, CO follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum ADU size of 1,200 sq ft
- –Maximum ADU size of 50% of the principal dwelling’s gross floor area
Detached ADU Size Limits
- –Maximum ADU size of 1,200 sq ft or 50% of the principal dwelling’s gross floor area, whichever is less
Max Units
- –1 ADU per lot (single-family detached)
Owner Occupancy
- –No owner occupancy requirement
Parking
- –1 space/ADU; required only if no existing off-street space (driveway/garage/tandem) and no block on-street parking; waived if on-street parking is allowed or an off-street space could serve the ADU
Rental Restrictions
- –Short-term rentals allowed in any dwelling unit with a city license; rental license/registration required before leasing
ADU State Law
What can you build in Colorado?
- –ADUs must be approved based on objective standards; no discretionary hearings allowed.
- –Historic properties: Local historic review may still apply in designated historic districts.
- –Exempt parcels: ADUs are not required to be allowed on parcels without adequate water/sewer, in floodways, or on certain historic properties.
- –HOAs cannot prohibit ADUs: HOA rules that conflict with the state ADU law are void.
- –Parking exceptions exist: In rare cases, one parking space may be required if there is no existing off-street parking and on-street parking is prohibited.
- –Local rules still matter: Building code, fire code, utility capacity, and life-safety standards still apply.
- –More permissive is allowed: Municipalities may allow larger ADUs, multiple ADUs, or additional housing types beyond what the state requires.
- –Local zoning controls whether ADUs are allowed at all.
- –HOA rules may still apply.
- –More permissive local rules are allowed.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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ADU rules in other Colorado municipalities
Rules change at the town line. Check the municipality your property is actually in.
Jefferson County