ADUs are allowed in New CastleTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for New Castle, CO
Is your property eligible for an ADU?
# of Parcels
2,273
Zoning districts
60
Zoning Districts:
2,272 parcels · 60 districts
CVR/F-1
13%(302)
R/1
13%(291)
CVR/F-6/PUD
6%(125)
R/3
5%(115)
Other
63%(1,439)
ADU Rules
What can you build in New Castle, CO?
New Castle, 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 is the lesser of 850 sq ft or 47% of the principal dwelling’s gross floor area; within Lakota Canyon Ranch PUD it is the lesser of 800 sq ft or 30% of the primary dwelling.
Detached ADU Size Limits
- –Maximum size of 850 sq ft or 47% of the principal building’s gross area, whichever is less (outside Lakota Canyon Ranch PUD)
- –Maximum size of 800 sq ft or 30% of the primary dwelling’s floor area in Lakota Canyon Ranch PUD, whichever is less
Max Units
- –1 ADU per principal building (town-wide)
- –1 ADU per lot (Lakota Canyon Ranch PUD)
Owner Occupancy
- –Owner-occupancy not required
Parking
- –1 space per ADU bedroom (in addition to principal-dwelling spaces); no maximum stated; exceptions: Lakota Canyon Ranch PUD allows stacked/tandem spaces to count toward the ADU minimum; Town Council may adjust requirements case-by-case.
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.
Garfield County