ADU rules in West Hartford

One accessory dwelling unit is allowed on a lot with a single-family house, and a detached backyard unit is expressly contemplated, but only in the six one-family residence districts: R-80, R-40, R-20, R-13, R-10 and R-6. In the Schedule of Permitted Accessory Uses (Chapter 177 Attachment 2, row 28) an ADU is a 'B' use in those six districts and is left blank everywhere else, and the schedule's key reads 'Not marked = Not a permitted use in the particular zoning district.' Two gates keep this short of a flat yes: § 177-23.1A(1) requires the lot to be no smaller than the district's minimum required lot size, which shuts out legally nonconforming undersized lots, and a single-family house standing on a multifamily, residence-office or business zoned lot has no listed ADU right at all. A detached unit must observe a side and rear yard equal to the principal dwelling's or 10 feet, whichever is less (§ 177-23.1A(5), rewritten 6-13-2023 to track CGS 8-2o(a)(4)), and § 177-23.1A(9) bars any additional curb cut to serve it.

Attached and interior units run through the same § 177-23.1 allowance and carry the same district and minimum-lot-size gates, so the value matches the detached one. That the section reaches units inside the house is plain from its own text: § 177-23.1A(3) caps the building footprint of 'a principal dwelling unit or accessory building', A(4) addresses units in basements, and A(6) requires the design to preserve the one-family character of 'the dwelling or building'. Basement conversions are the one type that is genuinely restricted: A(4) bars an ADU in a basement 'unless one wall within the unit opens to grade and contains both windows and walk-out ingress/egress', which rules out a fully below-grade apartment. Since the 6-13-2023 amendment, exterior access is required only 'as required by the applicable building or fire code' (§ 177-23.1A(7)), replacing the 2021 rule that the door sit on the side or rear and be invisible from the street.

§ 177-23.1A(2), as amended 6-13-2023, sets 'a maximum gross floor area of 1,000 square feet or 30% of the gross floor area of the principal dwelling unit, whichever is less.' The 2021 original was tighter: an 800 sq ft cap plus a 400 sq ft minimum, both of which the 2023 amendment removed. 'Gross floor area' is defined in § 177-2B as the sum of all floors measured by exterior dimensions, a more generous base than the 'net floor area' the state floor in CGS 8-2o(a)(3) uses. Bulk is limited separately: § 177-23.1A(3) holds the principal dwelling or accessory building to § 177-6D or § 177-20, and § 177-6D (Attachment 3) caps all buildings at 10% of lot area in R-80, 15% in R-40, 25% in R-20 and 30% in R-13, R-10 and R-6. Height is the trap for a detached unit: the district standards allow an accessory building only 1 1/2 stories and 15 feet, though § 177-20B lets an accessory building that observes the main building's yards rise to the main building's limit of 2 1/2 stories and 30 to 35 feet.

§ 177-23.1A(10) is flat: 'Either the principal dwelling unit or the accessory dwelling unit shall be owner-occupied.' It is an ongoing condition, not a test satisfied once at application, and A(11) enforces it with annual paperwork: an owner renting the ADU for income must file an affidavit with the Town Planner on or before December 31 each year certifying that one of the two units is owner-occupied. Connecticut's ADU statute leaves this alone. CGS 8-2o(a)(6) lists what regulations may not require (connecting passageway, exterior door beyond building or fire code, more than one parking space, familial, marital or employment relationships, occupant age minimums, separate utility billing, periodic permit renewals) and owner-occupancy is deliberately absent from that list. West Hartford reviewed § 177-23.1 against the statute on 6-13-2023 and kept the requirement.

§ 177-23.1A(8): 'At least one off-street parking space, subject to the requirements of § 177-32, shall be provided for the accessory dwelling unit, and the total required off-street parking for the principal dwelling shall not be reduced.' Because A(9) bars additional curb cuts serving the ADU, the space has to be worked into the existing driveway. One space is exactly the ceiling CGS 8-2o(a)(6)(C) permits for an accessory apartment, so the town is at the statutory maximum rather than above it. The town's general parking schedule now points at a moving target. § 177-32I(1), amended 6-13-2023 and 1-23-2024, requires 2 spaces per one-family dwelling 'unless a lesser number of spaces is required pursuant to C.G.S. § 8-2(d)(9), as amended from time to time', and § 8-2(d)(9) has since been rewritten twice over. Nov. Sp. Sess. P.A. 25-1 repealed CGS 8-2p outright effective 1-1-2026 (S. 53), so the parking opt-out West Hartford declined in 2023 no longer exists for any municipality, and S. 18 struck the old one-space-per-studio cap from 8-2(d)(9) effective 7-1-2026, replacing it with a bar on requiring 'a minimum number of off-street motor vehicle parking spaces for any residential development except as provided in section 8-3n'. New § 8-3n, also effective 7-1-2026, lets a municipality set minimums only for developments of more than sixteen dwelling units and otherwise bars rejecting a residential application solely for nonconforming parking absent a specific adverse public-health-and-safety finding. Because § 177-32I(1) incorporates 8-2(d)(9) 'as amended from time to time', the local schedule appears to follow the statute automatically, which would leave the general 2-space one-family requirement without force. How that interacts with the ADU-specific one-space rule in § 177-23.1A(8) is an open question this entry does not resolve: A(8) is its own requirement and is not written as a cross-reference to 8-2(d)(9). Confirm with the Planning and Zoning Division before relying on either reading.

Administrative, decided by staff, with no public hearing. Attachment 2 lists ADUs as a 'B' use, which the schedule's key defines as 'Permitted use subject to issuance of a building and/or zoning permit and subject to § 177-42B', and § 177-23.1B(1) confirms that an ADU application 'shall be subject to the site plan provisions of § 177-42B'. Under § 177-42B(1) the Town Planner, not the Town Plan and Zoning Commission and not the Town Council, must approve, disapprove or approve with modification within 65 days, the same deadline CGS 8-2o(b) sets for as-of-right accessory apartment decisions. Neighbours get notice but no hearing: § 177-23.1B(2) has the Town Planner mail a copy of the application to all adjoining owners by certificate of mailing, and B(3) requires the applicant to post a sign visible from the street from filing until a decision. Site plan conformance review does not defeat as-of-right status, since CGS 8-1a(b)(3) excepts 'a determination that a site plan is in conformance with applicable zoning regulations'.

The ordinance assumes ADUs will be rented: § 177-23.1A(11) speaks of 'an accessory dwelling unit which is rented for income' and simply requires the annual owner-occupancy affidavit. Nothing in § 177-23.1 sets a minimum lease term, caps the rent, requires a rental licence, or addresses selling the ADU separately from the house. West Hartford has no short-term rental regime: a full-text search of the Code on 2026-08-05 turned up no short-term rental use, licence, registration or prohibition anywhere, and the zoning definition of 'dwelling' in § 177-2B excludes hotels, motels, boarding and rooming houses and tourist homes, so transient lodging is not an established residential use in the one-family districts. That silence is the town's choice: CGS 8-2o(a)(7)(B) expressly preserves 'the ability of a municipality to prohibit or limit the use of accessory apartments for short-term rentals or vacation stays', and West Hartford has not exercised it, so this is a field to re-check if the Council ever takes up short-term rentals.