Marlborough board adopts law to allow detached accessory dwelling units in select zones

The Marlborough Town Board adopted Local Law No. 1 of 2026 on Jan. 12, allowing detached accessory dwelling units (ADUs) on single-family lots in R-1 and R-Ag-1 districts and in the R district where town water and sewer are available. The board also adopted its FEAF Part 3 and issued a SEQRA Negative Declaration, concluding the change would not produce significant environmental impacts.

Supervisor Corcoran read the law’s definition during the meeting: "A detached accessory dwelling unit ('ADU') is independently habitable and exists separately from the primary residence on a single lot." The local law caps ADUs at two bedrooms, sets a gross floor-area range of 400 to 900 square feet (with ZBA variance authority to adjust where needed), requires two off-street parking spaces in addition to those required for the primary residence, and forbids short-term rentals and bed-and-breakfast use of ADUs.

The board discussed referrals and recommendations from the Town Planning Board and the Ulster County Planning Board (UCPB). The UCPB had urged allowing all ADU types and extending allowances into the C commercial zone; the Town Board adopted the change only for detached ADUs and declined, by majority-plus-one votes, to expand ADU types or to add C-zone properties, noting concerns about enforcement and preserving commercial district character.

The law assigns administration and enforcement to the Code Enforcement Officer, requires Ulster County Department of Health certification of adequate water/sewer for new ADUs, and specifies that either the primary dwelling or the ADU must be the property owner’s primary residence. The local law becomes effective upon filing with the New York State Secretary of State.