What is an ADU?

An Accessory Dwelling Unit (ADU) is a smaller, self-contained residential unit located on the same lot as a primary residence, such as a single-family house or a small apartment building. ADUs are intended to be secondary to the primary residence and are sometimes referred to as in-law suites, granny flats, or accessory apartments. ADUs can be classified by their location:

• Internal ADUs are located within the primary residence, such as in a basement or converted attic.

• Detached ADUs are separate structures, such as carriage houses or converted garages.

Why ADUs?

Accessory Dwelling Units (ADUs) diversify local housing choices, offering a flexible, non-subsidized option for people across all income levels and life stages. By adding housing units with minimal adverse effects and respecting neighborhood character, ADUs also serve as a valuable tool for preserving historic structures.

Image description: On the left is a graphic showing an "internal" ADU, where the accessory unit is located within the primary residence. On the right is a graphic showing a "detached" ADU, where the accessory unit is a separate structure adjacent to the primary residence.

ADU Resources

• City Ordinance (NO. C-62)

• Newton ADU webpage

• Massachusetts State Law

• ADU Building Permit Application

• Inspectional Services ADU webpage

• Informational Brochure

What is De Minimis?

De minimis changes are small, limited alterations to a legally nonconforming residential building that the City considers minor enough not to negatively affect the neighborhood. These changes are allowed by right (without a special permit) if they meet specific size and setback requirements, and apply only to the nonconforming portion of the building. Examples include modest additions, dormers, decks, porches, bay windows, and certain height or facade adjustments, as long as they stay within defined square-footage and setback limitations provided by the Zoning Ordinance. Larger changes, changes in use, or expansions beyond these limits require a special permit.

De Minimis Resources

Approved Zoning Amendment - #375-24

What is the Residential Facade Build Out Ratio?

The ratio of the width of the entire residential front elevation of the building (A in the diagram) to the lot frontage along the primary front lot line (B in the diagram). This ratio cannot be more than 60% of the footage of the entire residential front elevation (B).

What part of the building counts as the Residential Front Elevation (A)?

Any exterior wall of the building that faces the primary lot line is counted as part of the residential front elevation. The building may be placed anywhere within the allowed building area (determined by setback requirements). Any portions set back 20 feet or more from the residential front elevation are excluded from the facade calculation.

What are the exemptions to following this facade ratio?

1. Buildings on lots that have 50 ft or less of frontage

2. Buildings, or any part of the building that are smaller than 1.5 stories (22' max for sloping roofs and 18' max for flat roofs)

What kind of buildings does this apply to?

This applies to all Single-Family, Detached and Two-Family Detached building types.

Can I increase the Front Elevation with a ratio greater than 60%?

In order to exceed the ratio, you must apply for a special permit, which is granted by the City Council.

What is the de minimums allowance?

If the building’s Facade Buildout Ratio is already non confirming, you can make alterations or additions that increase the width of the home’s front façade by up to 10% of the width of the Building Front Elevation.

What is the purpose of this?

The goal of creating a facade ratio is to guide newly constructed homes to be more contextual from the street.

Facade Ratio Resources

Approved Zoning Amendment - #28-25

Signed Council Order - #28-25

What is the change?

The new amendment removes parking requirements for businesses in and around Newton’s village centers within the BU1 and BU2 zoning districts.

Why remove this requirement?

Previously, new or expanding businesses were required to provide off-street parking, and if unavailable, had to go through the special permit process to waive the requirement.

This change cuts unnecessary time and makes it easier and faster for businesses to open, grow, and fill vacant storefronts. It's a simple step that supports a more vibrant and business-friendly Newton without affecting parking availability in practice.

Parking Regulations for Commercial Uses Resources:

Approved Zoning Amendment - #181-24

Signed Council Order

What is MRT zoning?

Multi-Residence Transit (MRT) zoning is part of the Village Center Overlay District (VCOD). The MRT zone helps facilitate the preservation of existing homes through conversion to multiple units and new, small-scale, multi-family buildings similar in size to the surrounding residential neighborhoods. This zone acts as a transition between the mixed-use cores of village centers and surrounding residential neighborhoods. As an overlay district, the new zoning allows the current zoning to remain while giving property owners the option to build according to either. Essentially, this new zoning allows for the preservation of existing homes, while increasing housing supply.

MRT development types:

• By right
• By special permit
• Adaptive reuse by right
• Multiple buildings on a lot by adaptive reuse by site plan review

MRT Resources:

Click HERE for a guide on Multi-Residence Transit (MRT) zoning