Town Meeting Articles 28 & 29 on ADU zoning (Updated)

Above: At a hearing on Monday, the Planning Board went through its draft presentation for ADU zoning changes on the Warrant for the upcoming Annual Town Meeting. (image cropped from video)

On April 7th, the Planning Board will ask voters to approve revised bylaws for Accessory Dwelling Units (ADUs). The bylaws will replace the current Town zoning for Accessory Apartments.

The intent is to address changes in state laws for ADUs that went into effect on February 2nd. Those changes are in conflict with the Town’s current bylaws, adding some rights that the Town disallows.

The board pitches that the changes will remove the conflicting language and “protect the town’s interests by providing clarity in the zoning code”. (The changes could also open up more opportunities for projects larger than what the state law allows by right. But the limitations there are still quite strict.)

Opponents argue that the board’s proposal under Annual Town Meeting Articles 28 & 29 goes too far in adding local oversight.

Background on the new state laws

At issue is the new laws and regulations under the Affordable Homes Act signed by the Governor last August. The state now allows some Accessory Dwelling Units (ADUs) up to 900 sq ft to be built by right within single family zoning districts without requiring a special permit. That wasn’t previously allowed in Southborough. (Especially new is the allowance that the dwellings don’t have to be physically connected to the original home.)

An ADU is defined as “a self-contained housing unit inclusive of sleeping cooking and sanitary facilities on the same lot as a principal dwelling. It maintains a separate entrance either directly from the outside or through an entry hall or corridor shared with the principal dwelling.”

Shapes and styles include detached units, attached units, interior upper level units, interior lower level units, above garage units, and garage conversions. (See depictions right from the state’s website.)

Under revised state laws, the “right” for adding an ADU doesn’t apply to every residential unit under 900 sq ft. It is also capped at half the gross floor area of the “principal dwelling unit” of the single family home the ADU would be “accessory” to.¹ And only one by-right ADU is allowed per property.

Local zoning laws can be designed to allow bigger projects and/or more ADUs by right (though not to further restrict it). 

There are limitations, to what is protected as by-right. Local zoning bylaw requirements for building size limits and required “setbacks” between properties still apply. And towns don’t need to allow mobile homes or short term rentals. And Planning Chair Meme Luttrell has highlighted that the law still allows Towns to require Site Plan review. But that has limits — and the Southborough Planning Board’s right is being questioned.

ATM Article 28 — Proposal and Disagreements

The Planning Board’s first ADU Article doesn’t expand the by-right project use beyond state laws and it fully takes advantage of allowed limits. The zoning clarifies that mobile homes can’t be used as ADUs. ² The board is also adding a “prohibition on short term rentals” less than 31 days.

The bylaws would also require even the by-right projects to go through an “Abbreviated Site Plan Review” through the Planning Board. State’s regulations allow that except for:

Site Plan Review concerning the Protected Use ADU that is not clear and objective or imposes terms and conditions that are unreasonable or inconsistent with an as-of-right process as defined in M.G.L. c. 40A, § 1A.

Members of the Select Board and Advisory Committee have argued that the review described in the Planning Board’s Articles add too much process and are too subjective. (That was the main reason for the Select Board’s vote to “Not Support” the Articles.)

But there is an even bigger hurdle for the board on that issue. Southborough’s Building Commissioner has opined that the Site Plan Review is not enforceable unless additional zoning changes are made that aren’t covered by Planning’s Articles.

At the March 24th Planning Board Meeting, Town Planner Karina Quinn read from Commissioner Lund’s feedback on the Articles. He interpreted that under the state law, the ADU doesn’t change the primary use of the residential properties. His comment letter to the board explained:

Unless the local bylaw explicitly reclassifies lots with ADUs as something other than single family they should still be considered single family properties with an accessory use and exempt them from site plan review.

Luttrell disagreed, stating that the site plan is allowed under state law and that the language was written by Town Counsel. She adovated that the public review allows transparency.

Lund’s opinion has serious implications, since he is the Town’s Zoning Enforcement Officer. It would be up to him to determine whether someone who pulls a building permit has the right to proceed with a project without going through the Planning Board’s process. For that reason, Planning Member Marnie Hoolahan said she was very concerned about being on a different page than Lund. Luttrell said that the board should reach out to Town Counsel for his opinion on Lund’s stance.³

Even if the Commissioner changes his opinion, there will be pushback on Town Meeting floor over the “Abbreviated Site Plan Review”. Site Plan Review process that a single family homeowner doesn’t have to go through for other by-right additions to their homes.

The “Abbreviated” terminology is new in Southborough Zoning law (which currently refers to Major or Minor Site Plan Review). In the Article, it is described as allowing the board oversight “limited to” the following criteria:

1. The ADU should minimize tree, vegetation and soil removal and grade changes.
2. Architectural style should be generally compatible with the existing principal dwelling on the subject property.
3. The ADU shall be serviced with adequate water supply and sewer or septic service.
4. The Plan shall demonstrate adequate parking, as required hereunder and shall maximize convenience and safety for vehicular and pedestrian movement within the property and in relation to adjacent ways.

That review and process step was a bone of contention at the Select Board’s and Advisory Committee’s joint meeting on March 11th. In a discussion with Luttrell, members of the other boards opined the Articles were overcomplicated. Some were concerned that the review appeared to give the Planning Board too much discretion, especially under criteria 1 & 2. They objected to limiting the by-right intent of the state law written to encourage increasing the housing stock.

Luttrell characterized the review as “non-discretionary” since the board would have to approve site plans for under 900 sq ft ADUs as long as they comply with the law and regulations. She advocated that the point of a Site Plan Review is to allow neighbors to comment and the board to act as a mediator.

Select Board member Al Hamilton was the harshest critic, making a libertarian argument about overreach. He called the zoning Articles unnecessary since the state law would override Town bylaws.

Others agreed with some of his points, but appeared to wish a simpler Article had been proposed to remove any legal conflicts with the state law without adding local restrictions. Among the other issues the board raised with the Articles was banning short term rentals.

Luttrell referred to issues other communities have had with AirBnB type rentals. But others argued that it could be used to provide an income for residents. They offered the example of by families visiting St. Mark’s School as a possible use. Advisory Committee Chair Andrew Pfaff highlighted that it isn’t prohibited for any other housing in Southborough.

Lutrell worried that the short term rentals can open the door for “very loud obnoxious behavior”. Hamilton rebutted that the Town has noise ordinances.

The Select Board later voted to Not Support the Articles. Advisory’s chose to wait to share an opinion at Town Meeting.

ATM Article 29 — Proposal, Complications, and Disagreements

Under the second Article on ADUs, revised bylaws would streamline the process for applying for a Special Permit for larger than the “by right” units. The board has been describing it as allowing ADUs larger than 900 square feet. But Article 29 would keep in place a ratio restriction that is stricter than the new by-right use.

The biggest change for potentially adding to the housing stock under this section is eliminating a cap on the total number of Accessory Apartments allowed in town.⁴

The only other change is replacing the Zoning Board of Appeals as the authority for issuing the Special Permits. Currently, applicants go to the Planning Board to allow them to comment to the ZBA before that board makes its decision. Moving the permit to the Planning Board would expedite the process by enabling the board to simultaneously oversee the site plan review. 

The ZBA members worked with the Planning Board on the bylaw language for the newly by-right ADUs. But according to a comment on this story from member Mike Robbins, who was involved in early stages of the bylaw development, shifting the special permit authority wasn’t raised in those discussions.⁵ (Robbins’ comment noted that he personally opposes the authority shift.)

Other details seem to be status quo.

The Special Permitted projects would still prohibit using permits to allow multiple ADUs, short term rentals, or mobile homes as ADUs. And the Special Permits would restrict the “habitable floor areas” of ADUs the same cap in current zoning for Accessory Apartments — “25% of the habitable floor area of the entire dwelling plus that of any accessory building used for the accessory dwelling.”

That is a much tighter restriction than the by-right cap for units under 900 sq ft, which can be up to ½ of the gross floor area of the principal dwelling. Keeping that cap appears to prevent special permits for ADUs that are less than 900 sq ft but exceed the by-right ratio limits (when the primary dwelling has less than 1800 sq ft of gross floor area).

The fact that the two Articles use different terms (habitable/gross) and formulas for calculating the size limit ratio complicates the direct comparison. But it appears that in some instances, there would be ADUs that would exceed the size restriction allowed under a special permit yet the Town will have to allow under the by-right section of the bylaws.⁶

On Monday, Planning Vice Chair Jesse Stein did a run through the presentation drafted for Town Meeting. In it he noted “the spirit of [the bylaw changes] is to increase our affordable housing stock and diversity of housing”. The touted benefits for the ADUs were:

• Rental income for property owners
• Low-cost options for adult children and other relatives to stay in town
• More options for older adults seeking to stay in town
• Adding rental units to the housing inventory that are better for small households
• A more sustainable and economical way to add new growth than creating new single family home lots

In the March 11th meeting, Select Board Member Sam Stivers noted that the ZBA currently has the right to ignore the Planning Board’s comments on the special permits. He advocated keeping the ZBA as the authority, but didn’t specify why. He followed that if it does move to Planning, he’d like the ZBA to serve as the first appealing authority for rejected permits, rather than going straight to court. The Articles don’t specify the appeal path, and I’m not clear on what that is for special permits. (In the Town code, the appeal for site plans refers aggrieved parties appeal in court.)

In Monday’s Planning meeting, the first since the Select Board and Advisory Committee provided feedback at their joint meeting, Planning didn’t discuss the other board’s comments. As is their practice, the Planning Board continued its hearing on the zoning bylaws to resume 30 minutes before the start of Annual Town Meeting.

You can read the full text of both Articles here. For more on the Annual Town Meeting, including all of the Articles, click here.

Updated (4/2/25 8:44 am): After ZBA member Mike Robbins pointed out an error in my story, I corrected the information about the ZBA’s involvement in developing the bylaw Articles. Apparently, they did not discuss the concept of shifting the special permit authority from their board for the larger units (under Article 29). Their involvement was only with the language around the process for the by-right ADUs under Article 28.

1. Under state regulations, Gross Floor Area is “The sum of the areas of all stories of the building of compliant ceiling height pursuant to the Building Code, including basements, lofts, and intermediate floored tiers, measured from the interior faces of exterior walls or from the centerline of walls separating buildings or dwelling units but excluding crawl spaces, garage parking areas, attics, enclosed porches and similar spaces. Where there are multiple Principal Dwellings on the Lot, the GFA of the largest Principal Dwelling shall be used for determining the maximum size of a Protected Use ADU.” The cap impacts homes that have under 1,800 sq ft of gross floor area.
2. Southborough zoning bylaws do allow for mobile homes in residential zones, but they require special permit if they are used as a dwelling for more than 30 days per year. The proposed bylaw revisions wouldn’t change that.
3. Ultimately, the Building Commissioner has the final say on how to interpret the zoning code in Southborough, not Town Counsel. But, the attorney’s opinion and explanation for it could influence the Commissioner’s decision.
4. Under Southborough’s current zoning “The total cumulative number of accessory apartments permitted. . . shall at no time exceed 5% of the total number of one-family houses in Southborough at the beginning of the year in which the application is filed, based on the Assessor’s records. Residences containing apartments shall be counted as one-family houses for the purposes of this subsection.” That conflicts with the by-right state law. But it would presumably impact ADUs by special permit if not struck or amended.
5. I originally wrote, “The ZBA approved of the choice to shift the ADU hearings to Planning and members worked with the board to help determine some of the bylaw details.” As I noted in my comment replying to Robbins, that was a mistaken assumption I made based on Luttrell stating that the ZBA had been involved in the bylaw development. (At the point she made that comment, the discussion was focused on the process for by-right units.)
6. By my amateur reading — A home with 1,800 sq feet of gross floor area could add on an ADU that is up to 900 sq ft of gross floor area. But, if the owner of that property applied for a special permit to allow a larger apartment, it would be limited to 600 sq ft. The only way to get around that would be to also significantly expand the original primary dwelling area. Under the special permit to add a 901 sq ft ADU, the primary dwelling would also need to be increased by another 903 sq ft, more than doubling the original size of the home.