Lancaster, MA

Lancaster, Massachusetts’ Accessory Dwelling Unit (ADU) Rules

Last updated: 2024

Lancaster, MA Accessory Dwelling Unit (ADU) Rules

As of 4/22/2024

City Acceptance Rating:

5/10(10 is most accepting)

What you need to know about ADUs in Lancaster, MA:

ADUs have been possible in Lancaster under a special permit since 2007.  The town of Lancaster does not specify whether the ADU must be attached, detached, or retrofitted; however, they have specific requirements detailing the size, aesthetic, and desired purpose of the ADU.  

ADU permit requirements in Lancaster, NA:

A special permit is required for construction of ADUs in Lancaster.  

The ADU Rules in Lancaster, MA:

  1. The primary residence must have been built five years prior to building an ADU.

  2. Either the primary residence and ADU must be owner occupied.  Temporary absences are allowed for no more than 12 months.

  3. The habitable size of the ADU is limited to ⅓ of the habitable square footage of the existing dwelling and the proposed ADU or 1,200 square feet, whichever is less. 

  4. The ADU must have a separate entrance from the primary residence, there can be no more than one entrance door on a single side, and there cannot be any exterior staircases.

  5. The ADU cannot be designed to house greater than three people

  6. If not on town water and sewer, the owner must document that appropriate water and sewer modifications have been made to accommodate the needs of the ADU.

  7. There must be at least three parking spaces available.

  8. There must be a benefit to the community under the following conditions:

    1. There is a benefit to a community housing need or special need of the planned occupant.

    2. The compatibility of the design in relation to the existing structure and neighborhood.

    3. The construction impact to natural resources, privacy of neighbors, overall character of the neighborhood, and safety.

Resources:

https://ecode360.com/11813694 (scroll to the bottom of the page.  Section G)

Updates:

https://www.ci.lancaster.ma.us/sites/g/files/vyhlif4586/f/pages/la2689-220a_use_regulation_schedule.pdf - Indicates that special permit is still required
https://ecode360.com/LA2689/laws/LF1884287.pdf  - indicates there may be a new (unclear) zone that would make ADUs by right or just retrofit.  Unclear to me (sam) at this time.

Attached ADU, Convert Existing Space, Detached ADUChris LeeFriendliness Score N/A, Lancaster, Massachusetts, Western MA