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What Are You Allowed to Build at 21 Trenton St, Boston, MA, 02129?

Backyard Cottage

(Detached ADU)

Probably Not Allowed
This lot does not meet the requirements for a Detached ADU. A variance may be requested through your local zoning authority

In Home Apartment

(Conversion or Addition)

Probably Allowed
This property meets the requirements for an Internal ADU of up to 1,250 sq ft allowed By Right, or possibly more by Special Permit.

Swimming Pool

Probably Allowed
This property likely meets the zoning requirements to build a swimming pool. Based on applicable zoning limits, the estimated buildable area for a pool. Final feasibility may depend on site-specific conditions and local interpretation.

Single Family

Probably Not Allowed
This lot does not meet the zoning requirements to build a Single-Family home. A variance may be requested through your local zoning authority

Multi Family

Home Addition

Probably Allowed
We estimate you can expand this property by up to 586 sq ft under current zoning rules. This may allow for a horizontal addition, a vertical addition, or both, depending on design and permitting.

Property facts

Streetview picture of 21 Trenton St, Boston, MA, 02129

Zoning Jurisdiction

BOSTON

Parcel ID

0203108000

Property Type

Two Family

Zone

Art62_3F-2000

Year Built

1880

Lot Size

1,499 sq ft

Gross Building Area

880 sq ft

Gross Floor Area

2,412 sq ft

Estimated

Living Area

2,412 sq ft

Basement Area

0 sq ft

Impervious Surface

880 sq ft

Estimated
58.7%of lot coverage

ADU rules for Boston, MA

Based on public data and AI. Check with a pro. Read More

© 2026 TheBuilder AI Inc. d/b/aFutureLot. All rights reserved.

What Are You Allowed to Build at 21 Trenton St, Boston, MA, 02129?

Backyard Cottage

(Detached ADU)

Probably Not Allowed
This lot does not meet the requirements for a Detached ADU. A variance may be requested through your local zoning authority

In Home Apartment

(Conversion or Addition)

Probably Allowed
This property meets the requirements for an Internal ADU of up to 1,250 sq ft allowed By Right, or possibly more by Special Permit.

Swimming Pool

Probably Allowed
This property likely meets the zoning requirements to build a swimming pool. Based on applicable zoning limits, the estimated buildable area for a pool. Final feasibility may depend on site-specific conditions and local interpretation.

Single Family

Probably Not Allowed
This lot does not meet the zoning requirements to build a Single-Family home. A variance may be requested through your local zoning authority

Multi Family

Home Addition

Probably Allowed
We estimate you can expand this property by up to 586 sq ft under current zoning rules. This may allow for a horizontal addition, a vertical addition, or both, depending on design and permitting.

Property facts

Streetview picture of 21 Trenton St, Boston, MA, 02129

Zoning Jurisdiction

BOSTON

Parcel ID

0203108000

Property Type

Two Family

Zone

Art62_3F-2000

Year Built

1880

Lot Size

1,499 sq ft

Gross Building Area

880 sq ft

Gross Floor Area

2,412 sq ft

Estimated

Living Area

2,412 sq ft

Basement Area

0 sq ft

Impervious Surface

880 sq ft

Estimated
58.7%of lot coverage

ADU rules for Boston, MA

Based on public data and AI. Check with a pro. Read More

© 2026 TheBuilder AI Inc. d/b/aFutureLot. All rights reserved.