Hudson legal committee reviews draft local law to allow accessory dwelling units

Hudson legal committee members discussed a draft local law to allow accessory dwelling units (ADUs) at their Feb. 5 meeting, focusing on definitions, where ADUs would be permitted, how to handle preexisting nonconforming buildings, and whether permitting should be handled administratively or by the planning board.

Crystal, a staff member who drafted the outline, told the committee she reviewed recent municipal ADU laws and guidance and assembled a preliminary local law. “What I've started to do ... is ... put together the preliminary parts of what would be a local law,” she said, summarizing key elements: an ADU would be a subordinate dwelling either within the principal dwelling or as a detached structure (for example, carriage houses above garages), with separate ingress and egress and entirely separate living quarters. Crystal also said the city’s zoning code currently lacks a definition for a principal dwelling unit, and that would need to be added to the code.

The draft assumes ADUs would be permitted where single‑family dwellings are allowed and would be limited to one ADU per parcel, with common ownership retained so the accessory unit is not subdivided into a separate lot. Crystal recommended that new ADUs meet current setback requirements and that preexisting nonconforming structures be allowed to host ADUs without requiring a separate variance process; she recommended those instances go to the planning board for site plan review. “Any new ADU ... should meet the setback requirements of the zoning code. But anything that's preexisting ... should be permitted in those structures ... without having to go through the variance procedure,” Crystal said.

Committee members raised practical and policy tradeoffs. One member representing the Fourth Ward noted small, deep lots where building placement in front of an existing home could be appropriate and cautioned that requiring rear siting only would not work for every lot. That member added, “I think it should be open to whoever would want to rent, and I think that people should also be able to rent these as short term,” arguing against limiting occupancy to relatives. Another member urged sensitivity to Hudson’s historic character, saying ADUs should be sited to preserve aesthetics and asking whether separate entrances would be required; Crystal replied that separate living quarters typically require separate kitchen and bathroom facilities and that separate or clearly separated entrances are normally desired.

Members discussed two permitting approaches: (1) administrative approval by the building department for ADUs that meet all zoning and building requirements; or (2) planning board review for conditional or site plan approval where lots or structures are nonconforming, to assess impacts such as driveway access and overall density. Crystal cautioned that comprehensively revising all setback requirements across residential districts would be a substantial undertaking and that adopting a focused ADU law first could preserve eligibility for grants tied to having an ADU ordinance in place.

The committee did not take a formal vote on the draft. Members agreed to take Crystal's materials away for additional review, obtain input from city staff (including Craig), and return to the committee with suggested edits and recommendations for whether permitting should be administrative or require planning board review.

Next steps identified by the committee included additional staff review, consideration of whether short‑term rentals should be permitted in ADUs, and follow‑up with the city planning and building departments before a final draft is prepared for council consideration.