ADU rules in Bridgeport

A detached backyard cottage containing an accessory apartment is allowed, but only in the four Neighborhood zones and not on the same terms in each. It is allowed as of right on House A lots in N1, House C lots in N3 and House D lots in N4, and on House B lots in N2 only with a Planning and Zoning Commission special permit. Accessory apartments are marked 'not allowed' on every other building type table, including House A in the NX1 and NX2 Neighborhood Mix zones, Double House A, Row Building and all mixed-use, commercial, industrial and public-institutional zones. Siting gates bite as well: 3.170.2 caps one backyard cottage per lot and requires a rear yard at least 45 feet deep measured from the rear of the principal building to the rear lot line, plus a 20 foot by 20 foot landscape area between the two buildings, which rules out many of Bridgeport's narrow city lots.

An internal or attached accessory apartment is allowed as of right in N1 (House A), N3 (House C) and N4 (House D), where the building type tables read '1 in House or Backyard Cottage' (N3 reads 'up to 2; 1 in House and/or 1 in Backyard Cottage'). It is not available in N2: the House B table allows only '1 in Backyard Cottage with special permit', so a mid-century N2 homeowner cannot convert an attic or basement to an accessory apartment at all. It is also barred in NX1 and NX2 and in every non-Neighborhood zone. Where allowed, 4.70.2(B)(3) recognizes conversion of interior space such as an attic or basement, an addition to the existing dwelling, conversion of an existing accessory building, and construction of a new principal dwelling with an internal accessory apartment.

Section 4.70.2(B)(5) sets the unit cap at the lesser of 49 percent of the principal dwelling's gross floor area (excluding any attached garage) or 800 square feet, and excludes garage areas, basement areas with less than 7 feet of ceiling height, and other non-living space from the gross floor area calculation. A detached unit must also satisfy the backyard cottage envelope in 3.170.2(D): maximum floor area of 800 square feet or 50 percent of the rear yard area, whichever is smaller, one story of height (1.5 stories where the principal building is 2 or more stories, using the principal building's floor-to-floor heights), facade materials similar to the principal building, and a roof type allowed on the principal building. The 800 square foot ceiling is absolute, so on principal dwellings above roughly 1,650 square feet the percentage test stops mattering.

Bridgeport does not impose a literal owner-occupancy mandate, but it comes to nearly the same thing: 4.70.2(B)(4)(a) provides that no more than one of the dwelling units on a lot occupied by an accessory apartment may be a rental dwelling unit, so the house and the accessory apartment can never both be rented out. Before any permit issues, 4.70.2(B)(4)(c) requires the owner to record a deed restriction with the town clerk agreeing to these rental restrictions and to notify all prospective purchasers; the restriction runs with the land and binds heirs, assigns and later purchasers, must be on a form prescribed by the zoning administrator, and proof of recording must reach the zoning administrator before permits issue. In practice one unit must be held by an owner or other non-paying occupant. Connecticut's statewide accessory apartment statute does not disturb this: the list of prohibited requirements in CGS 8-2o(a)(6) deliberately omits owner occupancy, so local owner-occupancy and single-rental rules survive.

Section 4.70.2(B)(6) states plainly that no additional parking is required for an accessory apartment, with the single proviso that any existing required parking for the principal dwelling unit be maintained or replaced on site. That proviso is close to empty in Bridgeport, because 8.20.1 provides that the zoning code does not establish minimum off-street parking requirements anywhere in the city (only accessible spaces under the state building code, and Table 8-1 maximums that cap rather than compel parking). This is more generous than the one-space ceiling that CGS 8-2o(a)(6)(C) would allow. The Planning and Zoning Commission tried to reverse course on 6-30-2025 with text amendment 25-23, which would have re-established minimum off-street parking for new and expanded residential uses in every zone except DX1 and DX2; the motion to approve failed 4 to 5 and the amendment was denied, so 8.20.1 stands.

In N1, N3 and N4 an accessory apartment is an administrative matter: the use table marks it allowed, and the applicant files for a certificate of zoning compliance under 11.110, on which the zoning official must act within 45 days of a complete application, then a building permit whose plans the building official reviews for building and life safety code compliance under 4.70.2(D). Filing runs through the city's Park City Portal. In N2 the House B table conditions the only available accessory apartment (a backyard cottage) on a special permit, which under 11.50 means a preapplication review, a noticed Planning and Zoning Commission public hearing with mailed notice to owners within 100 feet, written findings, and a discretionary vote. Bridgeport really does route second units in N2 through that hearing: 2025 and 2026 PZC agendas include 25-24 (145 Ocean Ave.), 25-35 (1245-1255 Lindley St.), 26-11 (412 Jennings Ave.) and 26-21 (1265 Lindley St.), each a special permit and site plan review for a second dwelling unit in the N2 zone.

Section 4.70.2(B)(4) allows exactly one rental dwelling unit on a lot that contains an accessory apartment, bars accessory apartments from being used as short-term rentals, and bars renting them for periods of less than 31 consecutive days. The prohibition runs the other way too: 4.30.3(D) provides that short-term rentals are not permitted on lots occupied by an accessory apartment, and the short-term rental use itself is marked not allowed on every House building type table. The rental restrictions must be recorded as a deed restriction with the town clerk before permits issue, on a form prescribed by the zoning administrator, and they run with the land. A detached unit cannot be spun off: 3.170.2(G) provides that backyard cottages may not be sold separately from the principal detached house. Connecticut law leaves all of this in place, since CGS 8-2o(a)(7)(B) expressly preserves a municipality's ability to prohibit or limit accessory apartments as short-term rentals.