ADUs are allowed in Unincorporated SummitTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated Summit, CO
Is your property eligible for an ADU?
# of Parcels
14,883
Zoning districts
139
Avg Parcel Value
$1,049,821
Median Parcel Size
0.50 acres
Zoning Districts:
14,984 parcels · 139 districts
R-2
14%(2,089)
R-25
12%(1,808)
COP-PUD
11%(1,696)
R-6/PLAN
8%(1,190)
Other
55%(8,201)
ADU Rules
What can you build in Unincorporated Summit, CO?
Unincorporated Summit, 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 1,000 sq ft on lots under 5 acres and 1,400 sq ft on lots 5 acres or larger for an internal or attached ADU.
Detached ADU Size Limits
- –Maximum detached ADU size of 1,000 sq ft on lots under 5 acres; 1,400 sq ft on lots 5 acres or more.
Max Units
- –1 ADU per parcel (single-family or duplex)
Owner Occupancy
- –Owner-occupancy not required; restricted unit must be deed-restricted
Parking
- –1 space/ADU for studio or 1BR; 2 spaces for 2+BR; must park in a designated paved or graveled area; tandem parking allowed without relief; on a single-family lot, one space may be in the setback if at least 5 ft from property lines and meets Section 3505.13.
Rental Restrictions
- –Short-term rental of the restricted ADU is prohibited; it may only be rented long-term (at least 6 consecutive months) to Qualified Occupants, relatives, or retirees.
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