Compare ADU rules across Connecticut

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.

Ordinance read August 2026

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.

Ordinance read August 2026

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.

Ordinance read August 2026

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.

Ordinance read August 2026

Danbury states no owner-occupancy rule for accessory apartments because it creates no accessory apartment use to regulate; the regulations are silent rather than permissive, which is why this reads 'unknown' rather than 'no'. Owner occupancy does surface nearby: Section 2.B defines both a 'Boarding house' and a 'Rooming house' as a building 'that is the primary residence of the owner,' and Section 4.B.5.b permits rooming and boarding houses in the RMF-4 zone only. Note that CGS 8-2o never barred municipal owner-occupancy mandates; they are absent from the subsection (a)(6) prohibition list, so Danbury could have imposed one even had it complied instead of opting out. If the Zoning Commission reinstates accessory apartments, read this field fresh.

Ordinance read August 2026

There is no ADU permit pathway of any kind, so no review type can be recorded. Zoning permits under Section 10.B.1 are ministerial, issued by the Zoning Enforcement Officer, but only 'upon a finding by the Zoning Enforcement Officer that the proposed activity is in compliance with the Zoning Regulations,' which an accessory apartment never is. The variance route is closed by name rather than merely difficult: Section 11.B.2.a provides that 'No use variance shall be granted by the Zoning Board of Appeals for any parcel located within a RA-8, RA-20, RA-40, or RA-80 zone,' and Section 11.B.2.d adds that the Board 'shall not grant a variance to allow a use not permitted presently under any zone in these Regulations.' The only realistic routes are a Zoning Commission text amendment or a map change to a district where two family dwellings are permitted.

Ordinance read August 2026

Detached (free-standing) accessory apartments are allowed only in the Residence AAA, AA, and R-3 zones. Section 3.2's use table confirms the limit, listing 'Accessory Dwelling Units (Detached)' as an accessory permitted use under AAA, AA, and R-3 while leaving the R-2 and A columns blank. Section 13.3.H adds gates that bite on older lots: the lot must meet the applicable zone's minimum lot area (so a legally nonconforming undersized lot is disqualified), the structure must meet the setbacks and other design requirements that apply to primary structures rather than to accessory buildings, and the primary structure must not already contain an accessory apartment. Detached units are unavailable in the Residence R-2 and A zones, in the multi-family B and C districts (where Section 5.2.2.C allows attached units only), and in the Beach District. The Town Plan and Zoning Commission loosened this on 3-22-2022 by striking an older two-acre minimum lot requirement and substituting the applicable zone's minimum lot area.

Ordinance read August 2026

Detached accessory apartments were flatly banned in Milford until an amendment that takes effect August 14, 2026. Section 3.1.1.7, adopted 2-10-2023, requires that 'Both the principal and accessory dwellings must be contained in one building.' On July 7, 2026 the Planning and Zoning Board voted 8 to 1 to amend 3.1.1.7 so that an accessory dwelling unit 'may be allowed in a detached structure, in accessory to a single-family principal dwelling located in Zones R-18, R-30 and RA where property/zone classification is minimum 18,000 square feet or greater', with only one accessory dwelling unit per property; on July 21, 2026 the Board set the effective date at August 14, 2026 by a 6 to 1 vote. That confines detached units to Milford's three largest-lot single-family districts (R-18 requires 18,000 sq ft, R-30 requires 30,000, R-A requires 43,560), so R-12.5, R-10, R-7.5 and R-5 lots, which cover much of the city, still cannot have one. A detached unit must also satisfy the ordinary accessory-structure limits: 15 ft maximum height, 10 ft rear and 10 to 15 ft side setbacks, and a footprint no greater than 50 percent of the principal building's footprint unless it is 600 sq ft or smaller.

Ordinance read August 2026

Attached and interior ADUs are allowed, but only as a special exception use in four residential districts and only on larger lots. Sections 60-20-140 (S-1), 70-20-150 (S-2), 80-20-150 (S-3) and 90-20-10.10 (T) list 'Accessory dwelling unit' among the special exception uses 'permitted, subject to approval by the Zoning Board of Appeals pursuant to Section 270-40', with site plan review under Section 280-60. Section 270-40-40.290.10.10 adds that ADUs 'shall be constructed only on lots totaling more than eight thousand (8,000) square feet', which is a real gate: the minimum lot area is 8,000 sq ft in S-2 and 6,000 sq ft in both S-3 and T, so a conforming lot in those three districts does not qualify and only S-1 (13,500 sq ft minimum) clears the threshold automatically. No ADU listing appears in the T-6, A-1, A-2, A-3 or any nonresidential district, and Section 30-20-10.10 defines the use as a unit 'subordinate to the primary residence on a single-family home parcel'.

Ordinance read August 2026

An ADU needs a discretionary special exception from the Zoning Board of Appeals, not staff sign-off. Each district section provides that special exception uses are 'permitted, subject to approval by the Zoning Board of Appeals pursuant to Section 270-40', and Section 270-40-20.20 requires the Board to 'make a specific finding, after a public hearing in the manner provided by law, that such use will not be prejudicial to the character of its neighborhood'. Section 270-40-20.30 further bars any grant 'until the said Board shall have first received and considered an advisory report thereon from the City Plan Commission', which has 30 days to report. Section 270-40-30 layers on eleven general standards, and the site plan goes to review under Section 280-60. This is exactly the discretionary review CGS 8-2o would forbid for as-of-right accessory apartments; New Britain can require it because it opted out on 12-14-2022.

Ordinance read August 2026

A detached ADU is allowed only where an accessory structure already exists. Zoning Ordinance Section 22.D.1 permits an ADU to be created 'within an existing principal structure or in an accessory structure or within the Building Envelope Dimensions thereof,' and Section 22.C.3 allows new construction only 'within the Building Envelope Dimensions of the existing structure' when an existing accessory structure is unsuitable for conversion. A backyard lot with no garage or shed therefore has no as-of-right detached path. The allowance is also limited to the RS-1, RS-2, RM-1 and RM-2 districts on a lot of at least 4,000 square feet, and the owner must live on the property. The city's own ADU Toolkit states the point plainly: 'New detached ADU's are not allowable under the current ADU Ordinance.'

Ordinance read August 2026

Interior conversions are the ordinance's main path: Section 22.D.1 allows an ADU 'within an existing principal structure,' which the City Plan Commission describes as 'converting a third floor into a new unit, fitting out a basement unit or converting an existing garage into a dwelling unit.' The gates that bite are the district list (Section 22 opening sentence permits ADUs only 'within the RS-1, RS-2, RM-1, and RM-2 Zoning Districts,' leaving out RS-3, RH-1, RH-2, RO and the business districts where single-family homes also sit), the 4,000 square foot minimum lot under Section 22.E.1, and the owner-occupancy rule in Section 22.G.1. An attached ADU built as a new addition outside the existing envelope is not allowed, and Section 22.E.5 bars raising the roof of an internal ADU beyond the principal structure's existing height without a variance.

Ordinance read August 2026

Two routes, both without a public hearing. Most ADUs are 'Permitted by Zoning Permit in accordance with Section 8.4.10': every ADU that complies with principal-building setbacks, plus attached ADUs converting a nonconforming portion of the principal building. Table 8.4.3 (Review Authority) makes the Zoning Permit a Planning and Zoning Director decision, appealable to the Zoning Board of Appeals. Detached ADUs that comply only with accessory-building setbacks, and conversions of existing accessory buildings, are 'Permitted by Site Plan Review in accordance with Section 8.4.5,' a Planning and Zoning Commission decision (no hearing required; CGS 8-3(g) site plan certification). For every ADU application, whichever route, the applicant must mail notice by U.S.P.S. with a Certificate of Mailing-Firm to all owners within 100 feet of the lot, and Zoning Permit decisions must be published in a newspaper at the applicant's expense.

Ordinance read August 2026

Stamford wrote its own ADU rules (App. 222-28, effective 10/11/2022) after opting out of the state ADU statute, and they allow detached ADUs but with a gate that commonly bites: an ADU (attached or detached) is allowed only on a lot that contains no more than one single-family dwelling AND has a lot area of at least 10,000 sq ft. That excludes conforming lots in the R-7 1/2 district (7,500 sf minimum) and most R-6 single-family lots (5,000 sf minimum), even though single-family homes are permitted there. A detached ADU must meet either the accessory-building standards or the district's single-family dwelling standards, and only one ADU is allowed per single-family dwelling. Two-family and multi-family properties, including legally nonconforming two- and three-family dwellings, are ineligible, and on septic lots the Health Department and EPB must first find the system sufficient for both units.

Ordinance read August 2026

The same regulation allows the ADU to be 'attached to or within the Principal Dwelling Unit' (basement, addition, or internal conversion), subject to the identical gates: a lot with no more than one single-family dwelling, at least 10,000 sq ft of lot area, one ADU maximum, and owner occupancy. Attached ADUs and ADUs within the principal dwelling must meet all requirements of the underlying zoning district. In single-family districts the ADU is excluded from the one-dwelling-per-lot density cap (Section 5.X.4.d note 1), so adding one does not make the lot nonconforming as to density.

Ordinance read August 2026

Detached ADUs are allowed on single-family properties in all nine residential zones (GBR-130, RC-120, RR-80, RA-40, RM-20, RM-15, RH-10, RA-20 and RA-15) and in the DB-5, CS-5, LS-5, GC-60, TC-80, MC-80 and PV-5 districts, but never in the M-1, LI-130, HI-60 or HM districts. The conditions bite: Section 6.3.2.K bars an ADU outright where the property does not meet the district's minimum lot size, a new detached structure needs a Site Plan Application rather than a plain Zoning Permit, and converting an existing detached garage or barn is permitted only if that structure already meets current setbacks. A setback-nonconforming detached structure can be converted only if it qualifies as a historic structure and only by Special Use Permit, with screening and Commission findings. New detached construction may not sit closer to the street than the primary dwelling, and detached ADU structures are capped at 30 feet or the district height limit, whichever is less, and at two stories. Since the March 4, 2026 amendments the permit for new detached construction is a Site Plan Application, not the Special Use Permit that applied before.

Ordinance read August 2026

An ADU inside the house is allowed by Zoning Permit in the same districts, but Section 6.3.2.B permits an ADU located within a principal structure only in a single-family residential structure of at least 2,000 square feet total gross floor area, exclusive of accessory buildings. That single threshold is the main thing keeping Stonington homeowners out: the Town Planner told the Planning and Zoning Commission at the October 4, 2022 opt-out hearing that reducing it 'is the main item that would enable more homeowners to permit ADU's,' and the March 2026 rewrite left it untouched. Section 6.3.2.F allows a building addition to accommodate an ADU provided all other requirements of the section are met, and Section 6.3.2.K's minimum-lot-size bar applies here too. Secondary access doors must be on the side or rear, and external stairs to upper stories must be at the rear.

Ordinance read August 2026

The use tables list the ADU as 'ZP/SPA' with a footnote pointing to Section 6.3.2 for the specific permit, and the answer depends on the kind of ADU. An ADU inside the house, or a conversion of an existing detached garage or barn that already meets the district's setbacks, needs only a Zoning Permit, signed off by the Zoning Official on the town's one-page Zoning Permit Application. Construction of a new detached structure containing an ADU requires a Site Plan Application under Section 6.3.2.M.1; that is a compliance review rather than a discretionary hearing, and Sections 15.3.2.A and 17.1.4 treat single-family dwellings and their associated accessory uses in residential districts as reviewed by the Zoning Enforcement Officer, though the regulations never say in so many words who decides a residential-district Site Plan Application for an ADU. Only one path is genuinely discretionary: converting a historic detached accessory structure that does not meet setbacks requires a Special Use Permit with a Commission hearing under Section 6.3.2.M.2.a. The March 4, 2026 amendments cut the permit for new detached ADU structures from a Special Use Permit down to a Site Plan Application and removed Architectural Design Review Board review of ADUs.

Ordinance read August 2026

There is no ADU owner-occupancy rule to report because Waterbury permits no accessory dwelling unit, so the Zoning Regulations contain no ADU occupancy provision. This is not a preemption question in any event: CGS 8-2o never prohibited owner-occupancy requirements, since they are absent from the list of forbidden conditions at 8-2o(a)(6). Waterbury does regulate rental ownership generally rather than occupancy: Code of Ordinances Section 160.06 requires any nonresident owner of residential rental property or a dwelling unit to file and keep on file with the Town Clerk a current residential address, or the address of an agent in charge if the owner is an entity.

Ordinance read August 2026

There is no ADU permit path to classify, because no accessory dwelling unit use appears on the Master Use Table. For context on how Waterbury reviews housing generally: uses marked ZP are acted on administratively by the Zoning Enforcement Officer under Section 11.03, uses marked SP go to the Zoning Commission and uses marked SE to the City Plan Commission under Section 11.04, and Section 11.03.01 requires a Zoning Permit for any new principal structure, any addition of residential units, any expansion of 50 percent or more of a principal structure's gross living area, and any change of use. A homeowner adding a second unit in RM, RH or RO therefore proceeds through the Zoning Permit route for a Two or Three Family Residence, not through an ADU permit.

Ordinance read August 2026

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.

Ordinance read August 2026

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.

Ordinance read August 2026