ADUs are allowed in Blue RiverTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Blue River, CO
Is your property eligible for an ADU?
# of Parcels
936
Zoning districts
7
Avg Parcel Value
$1,465,384
Median Parcel Size
0.67 acres
Zoning Districts:
936 parcels · 7 districts
R-1
79%(737)
PRD
19%(178)
T
1%(12)
UOP
1%(5)
Other
0%(4)
ADU Rules
What can you build in Blue River, CO?
Blue River, 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 size of 600 sq ft
- –Maximum size of 45% of the primary residence’s habitable floor area
Detached ADU Size Limits
- –Detached backyard cottages are not permitted; maximum detached ADU size is 0 sq ft.
Owner Occupancy
- –No owner-occupancy restriction.
Parking
- –ADU may have up to 2 off-street spaces; total lot outdoor parking may not exceed 5; spaces must be on the same lot, in a designated paved or graveled area, may be in tandem or in a garage, not in setbacks, and on-street/off-lot spaces do not count.
Rental Restrictions
- –Short-term rentals prohibited unless licensed; leases must exceed 30 consecutive days unless a short-term rental license is obtained.
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.
Summit County