To see the effect of additional restrictions, toggle the controls below. We’re currently awaiting guidance from the Executive Office of Housing and Livable Communities and the Attorney General's office on permissible restrictions—please consult your town counsel. Generally, though, setbacks and height limits are more than sufficient to ensure privacy and maintain neighborhood character, making additional restrictions unnecessary.

To generate the estimates in the results panel, we used assumptions based on historical data. You can adjust these assumptions to better reflect your municipality and observe how the results change.

This tool is designed to facilitate discussions by helping you visualize how the restrictions you implement might impact the number of lots eligible for an ADU in your municipality. For this reason, the tool focuses on dimensional controls, such as setbacks and lot size, rather than design standards, which you may also have authority to regulate. Additional guidance on ADU regulations from the Executive Office of Housing and Livable Communities is expected soon.

Generally, municipalities may impose reasonable restrictions and requirements for Site Plan Review, Title V requirements (septic systems), regulations concerning dimensional setbacks and the bulk and height of structures, and short-term rentals.

Municipalities cannot require owner occupancy for the ADU or the principal dwelling, require a special permit or other discretionary zoning approval for the use or rental of an ADU, require more than 1 parking space for an ADU located outside 0.5 miles from a commuter rail station, subway station, ferry terminal or bus station, require any parking for an ADU located within 0.5 miles from a commuter rail station, subway station, ferry terminal or bus station.