New website can tell you if your property qualifies for an accessory dwelling unit

Accessory dwelling units—detached cottage structures and attached “in-law apartment” additions—are often cited as an antidote to Newton’s housing shortage.

But Newton’s rules regarding ADUs are complicated, like everything else zoning-related, and many people don’t know if they can even build them where they live.

Two local entrepreneurs have come up with something to help with that.

Nitzan Achsaf of Newton and Avi Kaufman of Brookline have launched, a website that factors in maps, zoning codes and more to let people know what lots may or may not allow accessory dwelling units.

The project was inspired by their respective backgrounds—Kaufman has worked in real estate for 20 years and Achsaf has an extensive background in technology and project management—and the two hope it will help promote housing diversity in Newton.

“Part of the inspiration comes from seeing the housing crisis day in and day out,” Kaufman said. “I work with people who are struggling to find homes and who are stretching their budgets. And a large contributor to that problem is just the lack of supply.”

How it works

Achsaf and Kaufman went over the city’s zoning ordinances and maps and met with city officials to confirm their data.

“We took that, and with algorithms changed that into math equations, and we put that into our website,” Achsaf said. “And basically we’re tackling both the bylaws from the Newton municipality as well as the public data for different properties, and that’s how we build a report.”

The process took a few months to complete.

“It’s not easy to understand exactly what you can and cannot build based on your zoning and different parameters,” Achsaf said.

The website even factors in floor area ratio, which is the measurement of a building’s floor area compared with the size of the lot on which the home sits. Floor area ratio is also a factor in whether or not a home in Newton is allowed to have an ADU.

Fortunately, is less complicated to use than it was to create. Users just enter a property address into a search bar and within seconds, the website presents a report saying whether or not the property qualifies for an ADU, and why or why not.

Nitzan Achsaf, left, and Avi Kaufman, right, have created a website that lets Newton homeowners know if they’re allowed to add an accessory dwelling unit to their property. Courtesy Photo

For example, the Nathaniel Allen House is not eligible for an ADU. It’s a commercial building, it has historical property restrictions, and the Allen House is so big its floor area ratio wouldn’t allow an ADU even if it wasn’t a historic commercial venue.

If a property shows up as eligible for an ADU, the website shows what kind of ADU would be allowed—in-home apartment or backyard cottage—and even shows a map of the parcel and designs of potential ADU floor plans.

“We went through every single property record. If it’s in the city assessor’s database, then we did an analysis for it.” Kaufman said.

The property owner can then contact Achsaf and Kaufman, who have vetted contractors and other local construction professionals they can recommend to build the ADU. If the homeowner goes with those recommended businesses, gets a fee. And that’s how the website makes money.

“We’re not builders. We’re the connectors,” Kaufman said. “We want to show what might be possible and then be a resource for people to connect them with an architect and a builder.”

An ADU can serve a variety of purposes. It can provide rental income for homeowners, and it can allow adult kids to stay at home with privacy and for seniors to age-in-place with their families.

Newton currently has the potential for more than 15,000 ADUs, Achsaf said.