ADUs are allowed in MadisonTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Madison, CT
Is your property eligible for an ADU?
# of Properties
7,229
Owner-occupied
85%
Zoning districts
20
Avg Home Value
$719,268
Median Lot Size
1.05 acres
Avg Income
$161,334
Residential Types:
7,229 housing units
Single Family
90%
Other
10%
Zoning Districts:
8,585 parcels · 20 districts
RU-1
40%(3,410)
RU-2
13%(1,132)
R-1
12%(1,061)
R-2
10%(819)
Other
25%(2,163)
ADU Rules
What can you build in Madison, CT?
Madison, 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 of 800 sq ft or one-third of the dwelling’s floor area before conversion, whichever is less, for an internal/attached accessory apartment
Detached ADU Size Limits
- –Maximum size of 800 sq ft for a detached accessory dwelling unit
Max Units
- –1 ADU per single-family lot.
- –Duplex/multifamily: none specified.
- –ADU type: still 1 accessory apartment; no separate numeric cap by type (within the single-family dwelling or in an accessory building).
Owner Occupancy
- –Owner must permanently occupy either the principal or ADU
Parking
- –Min 3 off-street spaces total (for the principal dwelling and ADU); ADU-specific 3-space rule; Commission may reduce/waive; parking may be allowed within 1,000 ft; front-yard parking prohibited unless waived; generally follows Sec 8 (2 spaces/du).
Rental Restrictions
- –No rooming/boarding use within the ADU (no renting of rooms).
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.
South Central Connecticut County