ADUs are allowed in LyonsTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Lyons, CO
Is your property eligible for an ADU?
# of Properties
986
Owner-occupied
25%
Zoning districts
23
Avg Home Value
$95,326
Median Lot Size
0.22 acres
Avg Income
$132,288
Residential Types:
986 housing units
Single Family
81%
2-3 Family
1%
Apts (4+ units)
1%
Other
17%
Zoning Districts:
1,057 parcels · 23 districts
R-1
73%(767)
CD
4%(42)
EC
4%(40)
R-2A
4%(38)
Other
16%(170)
ADU Rules
What can you build in Lyons, CO?
Lyons, 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 equals the principal dwelling’s habitable area, or 800 sq ft if the principal dwelling is 800 sq ft or smaller; basement internal ADUs have no size limit.
Detached ADU Size Limits
- –Maximum detached ADU size up to the principal dwelling’s habitable area; if the principal dwelling is 800 sq ft or smaller, the ADU may be up to 800 sq ft.
Max Units
- –1 ADU per lot; 2 ADUs allowed if the lot is at least 0.5 acre; on lots 1 acre or larger, more than 2 ADUs may be requested.
Owner Occupancy
- –No owner-occupancy requirement for ADUs.
Parking
- –0 spaces/ADU; off-street parking not required; no conditional reductions; parking, if provided, follows Article 8 off-street standards.
Rental Restrictions
- –Short-term rentals prohibited; ADUs may not be leased for less than 30 days. Tiny Home ADUs used as ADUs: short-term lodgers prohibited and not eligible for short-term rental permits or B&B licensing.
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.
Boulder County