Southborough committee reviews housing needs, CommunityScale recommends 255-unit five-year production target

CommunityScale consultant Sarah Brent told the Town of Southborough Housing Production Plan Committee that, based on recent trends and census data, Southborough should add about 255 housing units over the next five years, including 28 units counted on the Subsidized Housing Inventory to meet a 10% “safe harbor” threshold. Brent said that produces a working annual production target of about 51 units.

The recommendation informed a broader discussion among committee members about priorities, timelines and potential locations. Committee members agreed to continue biweekly check-ins, confirmed a Tuesday, June 24 committee meeting at 6:30 p.m., and tentatively scheduled a joint meeting with the select board and planning board for Monday, July 14, at Town Hall to consider adopting the plan; CommunityScale indicated it could present at that joint meeting.

“Looking at growth, cost burden and vacancy rates, Southborough should add about 255 units over the next five years,” Sarah Brent said, attributing the figure to trends extended since 2010 and adjustments for vacancy and replacement needs. Brent described methodology that begins with historical trend extension, then adjusts for vacancy, replacement of aging housing stock and local measures of cost burden drawn from the 2023 American Community Survey (ACS).

Brent and committee members discussed key drivers behind the number: a projected net household growth concentrated in households earning above 120% of area median income (AMI), very low current vacancy rates for ownership (about 1.5%) and rental units (about 7.4%), and nearly 1,000 Southborough households spending more than 30% of income on housing costs with the greatest incidence below 60% AMI. Brent noted the HUD regional median family income used in the analysis (HUD AMI ~ $173,000) and that 120% of AMI is roughly $208,000.

The analysis also considered demographic change and housing type fit. Brent pointed out growth among residents aged 20–34 and increases in the 65-and-over cohort; she reported a conservative assumption that 1% of senior households in 3+ bedroom units might downsize annually, yielding an estimated 29 smaller units over five years. Committee members requested that CommunityScale add projections by age cohort and gross (not only net) population change to the materials circulated for review.

Committee members discussed site identification and strategy. Several members favored a theme-based approach—priority areas such as the Route 9 corridor, transit-oriented sites near the train station and downtown, and town-owned parcels—rather than naming many specific parcels in the published plan. CommunityScale said maps will show town-owned parcels (displayed as pink in the draft map) and layers denoting wetlands, Title 5 constraints, hydrography and wellhead protection, and that the map can be revised to distinguish open-space parcels.

Members also discussed housing types to meet the production target. The committee emphasized a multi-tiered strategy that includes multi-unit projects (to move the needle on unit totals), townhomes/duplexes for starter and downsizing options, accessory dwelling units (ADUs) and infill across neighborhoods. Committee members noted zoning and permitting constraints: a proposed ADU bylaw failed at the spring Town Meeting and the planning board is expected to revisit ADU rules for a possible fall Town Meeting; the committee also discussed a zoning cap for senior housing units.

Brent said CommunityScale can produce further analyses requested by the committee, including: (1) population projections by age cohort, (2) a clear data sources list for charts (Zillow, ACS, etc.), (3) a capacity estimate under current zoning for ADUs and “missing middle” infill types, and (4) a refined map that separates town-owned parcels that are open space from other town-owned land.

The meeting concluded with scheduling and process items: CommunityScale will circulate a revised slide deck and data files for committee review (Brent expected to send edits and the updated document later the same day or the next day), the committee will confirm check-in dates (two-week cadence with an optional check-in the week of July 17), and the committee chair will post the June 24 meeting and the planned July 14 joint meeting. The meeting was formally closed by voice motion and roll call.

Votes at a glance: A motion to close the meeting passed by roll call (Paul: yes; Ellen: yes; Doug: yes; Jesse: abstain).