ADU rules in Manchester

Section 7.6 of the zoning regulations allows one accessory dwelling unit on each lot that contains a single-family dwelling, and Item A expressly lets it be 'detached and located on the same lot as the principal dwelling'. The Accessory Use Summary Table for residential zones (Section 5.1) marks Accessory Dwelling Unit as 'P' (permitted) in the RR, AA, RA, RB, RC, PRD, EHD and FM zones, which covers Manchester's single-family neighborhoods, and Section 5.2 adds the Form-Based Zone. A detached ADU has to meet the underlying zone's setbacks, lot size, building frontage, building height and maximum buildable area (Item C) and the design standards in Item F, which require window and door placement that protects neighbors' privacy plus durable exterior materials and roof shapes matching or complementing the principal dwelling. The one hole in the coverage is the RM multi-family zone, where single-family dwellings are permitted but the accessory use table shows a dash for ADUs.

Section 7.6.A allows an ADU to be 'attached to or located within the principal dwelling', so an addition, a basement or attic conversion, or any other internal unit qualifies on the same as-of-right footing as a detached one. There is no requirement for a connecting passageway between the units and no requirement for a separate exterior door beyond what the building or fire code demands, matching the prohibitions in CGS 8-2o(a)(6)(A) and (B). Attached and interior units share the same 50 percent or 1,000 square foot size cap, one-space parking rule and design standards as detached ones. The regulations' definition tracks the state statute: an ADU is 'a separate dwelling unit that (1) is located on the same lot as a principal dwelling unit of greater square footage; (2) has cooking facilities; and (3) complies with or is otherwise exempt from any applicable building code, fire code, and health and safety regulations'.

Section 7.6.B caps an ADU at '50% of the net floor area of the principal dwelling, or 1,000 square feet, whichever is less'. Net floor area is defined as 'the actual occupied area not including unoccupied accessory areas such as corridors, stairways, ramps, toilet rooms, mechanical rooms and closets', so hallways, stairs, bathrooms and closets do not count against the cap. The 50 percent figure is new: it took effect March 30, 2026, when the Planning and Zoning Commission raised it from 30 percent and deleted the former Item D that had barred enlarging the principal dwelling's or an accessory building's footprint by more than 30 percent. There is no longer any minimum size either; the 350 square foot floor in the pre-2025 regulations disappeared in the June 9, 2025 comprehensive rewrite. Setbacks, lot size, building frontage, building height and maximum buildable area all follow the underlying zone (Item C), except in the Form-Based Zone, where Section 10.8.1 exempts ADUs from the dimensional requirements of Section 10.7.4.

Section 7.6 has six items covering location, size, dimensional standards, parking, curb cuts and design, and none of them requires the owner to live on the property. There is no owner-occupancy affidavit, no deed covenant, no annual certification and no permit renewal anywhere in the regulations for ADUs, and the pre-2025 provision (Art. II Section 1.03.01(v), adopted 11/15/2021 and effective 12/06/2021) did not require it either. This is Manchester's own choice rather than something state law forced: CGS 8-2o(a)(6) lists what accessory-apartment regulations may not require and pointedly omits owner occupancy, so Connecticut towns remain free to impose it. That the town knows how to write such a rule is clear from Section 6.4.A, which does require a bed and breakfast operator to 'be the owner of the property and reside in the bed & breakfast'. Several third-party ADU guides claim Manchester requires owner occupancy; it does not appear in either the current or the superseded regulations.

Section 7.6.D requires that 'at least one off-street parking space shall be provided for the accessory dwelling unit', which is what Manchester's regulations say on the books. Because the town complied with CGS 8-2o, that single space already sat exactly at the statutory ceiling: 8-2o(a)(6)(C) bars regulations from requiring 'any more than one parking space for any such accessory apartment, or fees in lieu of parking'. A broader state rule now cuts against requiring it at all, because since July 1, 2026 CGS 8-2(d)(9), as rewritten by Nov. Sp. Sess. P.A. 25-1 Section 18, provides that zoning regulations shall not 'require a minimum number of off-street motor vehicle parking spaces for any residential development except as provided in section 8-3n', and CGS 8-3n(a) forbids a zoning enforcement officer or commission from rejecting a residential application solely for nonconforming parking unless it finds the shortfall 'will have a specific adverse impact on public health and safety that cannot be mitigated'. CGS 8-3n(b) permits minimums only for developments containing more than sixteen dwelling units, and Manchester has adopted neither of the two 'conservation and traffic mitigation districts' that 8-3n(d) would let it use to require parking for smaller developments. Both texts are recorded here rather than reconciled: Section 7.6.D stands unamended, and separately Section 7.6.E bars an additional curb cut on the principal dwelling's street, though since March 30, 2026 a corner or through lot may get one on a different street with Town Engineer approval.

An ADU is a by-right accessory use with no discretionary hearing. Section 5.1 marks Accessory Dwelling Unit 'P' in every residential zone except RM and spells out what that means: 'a legal use of land and buildings that does not require approval or authorization by the Planning and Zoning Commission or Zoning Board of Appeals'. The administrative path is a Certificate of Zoning Compliance from the Zoning Enforcement Officer under Section 18.4.1.B, which bars occupancy of any new or altered building until the certificate issues, plus an ordinary building permit. The town's development-application page lists only special exceptions, inland wetland permits, subdivisions, erosion and sediment control plans and variances as commission-level filings, with no ADU application among them. Under CGS 8-2o(b) a decision on an as-of-right accessory-apartment application is due within 65 days of receipt.

Nothing in Section 7.6 or the ADU definition limits who may occupy the unit or on what terms: there is no owner-occupancy condition, no familial or employment relationship requirement, no minimum lease term, no tenant registration and no rent cap, so an ADU may be rented long-term without restriction. Manchester also has no short-term rental ordinance: neither Part I nor Part II of the Code of Ordinances on eCode360 (instance MA2034) contains a short-term rental, vacation rental or rental licensing chapter, and the zoning regulations reach short-stay lodging only through the separate Bed & Breakfast use, which is allowed by Special Exception in just the RR, AA and FM zones and requires the operator to own and live in the home. That silence is a policy choice the town can reverse at any time, because 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'. The regulations contain no provision permitting an ADU to be sold separately from the principal dwelling; Section 7.6 keeps both on one lot.