ADUs are allowed in KillingworthTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Killingworth, CT
Is your property eligible for an ADU?
# of Properties
2,273
Owner-occupied
90%
Zoning districts
6
Avg Home Value
$432,886
Median Lot Size
2.70 acres
Avg Income
$148,073
Residential Types:
2,273 housing units
Other
100%
Zoning Districts:
2,875 parcels · 6 districts
R
98%(2,817)
C
1%(38)
LB
0%(14)
I
0%(3)
Other
0%(3)
ADU Rules
What can you build in Killingworth, CT?
Killingworth, CT 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 is the lesser of 33% of the primary dwelling’s floor area or 950 sq ft
Detached ADU Size Limits
- –Maximum size is the lesser of 33% of the primary home’s floor area or 950 sq ft
- –With a Special Exception for an accessory caretaker apartment on qualifying large, conforming properties, maximum size is 1,600 sq ft
Owner Occupancy
- –Owner must occupy principal dwelling, ADU, or caretaker apartment
Parking
- –3 spaces per ADU (same as principal); parking for multiple uses computed separately and cumulatively; on-site parking unless a special exception allows off-site; fractions round up.
Rental Restrictions
- –Detached ADU: if deed-restricted as affordable, rents capped for 40 years (max rent ≤30% of income for families at 60% AMI).
- –Attached/Internal ADU: affordable units subject to 40-year caps/covenants and rent limits.
ADU State Law
What can you build in Connecticut?
- –Connecticut Public Act 21-29 (now CGS § 8-2o) established statewide ADU rules.
- –115 municipalities opted out of the state ADU provisions. In those towns, ADUs may still be allowed, but they are regulated solely under local zoning bylaws.
- –54 municipalities did not opt out and are subject to the state's default ADU standards. Local bylaws in these towns must allow at least the minimums required by state law.
- –At least one accessory apartment must be allowed as of right on any lot with a single-family home.
- –Towns must allow an ADU to be at least the lesser of 1,000 sq ft or 30% of the principal dwelling's Net Floor Area.
- –Setbacks, lot size, building frontage, lot coverage, height, and design requirements cannot be more restrictive than those applied to the principal dwelling.
- –Only one parking space can be required per ADU.
- –A passageway between units
- –A separate exterior entrance (unless required by code)
- –A relationship (e.g. familial or employment) between occupants
- –Age minimums for ADU tenants
- –Separate utility billing
- –Periodic permit renewals
- –Owner-occupancy is not required under state law, but towns may impose it.
- –Towns may regulate short-term rentals.
- –Requirements for wells or private sewerage systems still apply, but approval cannot be unreasonably withheld.
- –Towns may not condition ADU approval on fixing unrelated nonconformities on the lot.
- –No new utility connection fees may be charged unless the ADU is built with a new principal dwelling.
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 Connecticut municipalities
Rules change at the town line. Check the municipality your property is actually in.
Lower Connecticut River Valley County