Can I build an ADU in Wayland, Massachusetts?
Yes. Under the zoning amendment adopted in April 2025, one accessory dwelling unit per lot is allowed by right in the Single Residence District with a building permit. It can be no larger than half the main house's gross floor area or 900 sq ft, whichever is less, and it needs Board of Health septic approval and one off-street parking space.
| Allowed in Single Residence District | Yes, by right (one ADU per lot) [5] |
| Max size | 1/2 of the main home's gross floor area or 900 sq ft, whichever is less [4] |
| More than one ADU | Planning Board special permit (detached structure) [4] |
| Parking | 1 dedicated space (10 x 20 ft); none if within 0.5 miles of a transit or bus station [2] |
| Short-term rental | Not allowed; no rentals under 31 consecutive days [2] |
| Septic | Board of Health written approval before applying for the building permit [3] |
| Occupancy | Certificate of occupancy from the Building Commissioner required before use [6] |
What counts as an ADU
Wayland's 2025 ADU zoning article redefines an accessory dwelling unit to match state rules: a self-contained unit with its own sleeping, cooking and bathroom facilities on the same lot as the main house, inside it or in an accessory building, with a separate entrance that meets the building code. It can't be larger than half the main house's gross floor area or 900 square feet, whichever is smaller [1].
Where and how many
The amendment makes an ADU a use allowed by right in the Single Residence District [5]. One ADU per lot is allowed by right; the Planning Board may grant a special permit for more than one ADU in a detached structure [4].
Parking, rentals and septic
You need one dedicated off-street space for the ADU, 10 by 20 feet, on top of the main house's parking. No space is required if the lot is within half a mile of a transit or bus station. An ADU can't be used as a short-term rental, meaning stays under 31 consecutive days [2]. Before applying for a building permit, you need written Board of Health approval that your septic system can serve both units, or approval to connect to the Wastewater Management District Commission system [3].
Permits
File floor plans of the ADU and a plot plan with your building permit application to the Building Commissioner. Nobody can move in until the Building Commissioner issues a certificate of occupancy [6].
Where this text comes from
Our copy is the Planning Board's article as submitted for the April 2025 Annual Town Meeting, not the codified bylaw. Town Meeting adopted it (Article 19, Motion 1) as printed in the warrant, and the Attorney General approved it in part on July 28, 2025, disapproving a portion that conflicted with state law; we have not seen which portion. Our copy also lost its strikethrough formatting, so the old rules it replaced (owner occupancy, a 20,000 sq ft minimum lot, a two-year-old building) still appear in the text; they are no longer in effect. Under state law since February 2, 2025, a town can't require owner occupancy, a minimum lot size or a special permit for a first ADU. Confirm the current wording with the Building Department.
See how Wayland compares with 8+ other Massachusetts towns on accessory dwelling units (adus) →
Next steps
- Confirm with the Building Department (508-358-3600) that the 2025 ADU amendment was adopted as written, and get the current text of Zoning Bylaw §198-901.1.3.
- Get written Board of Health approval that your septic system can serve the house and the ADU (or approval to connect to the Wastewater Management District system).
- Prepare floor plans of the ADU and a plot plan showing the building(s) and the extra 10 x 20 ft parking space.
- Apply to the Building Commissioner for a building permit; do not occupy the unit until a certificate of occupancy is issued.
- For a second ADU in a detached structure, apply to the Planning Board for a special permit.
Common questions
- Can I build an ADU in Wayland, Massachusetts?
- Yes. Under the zoning amendment adopted in April 2025, one accessory dwelling unit per lot is allowed by right in the Single Residence District with a building permit.
- How big can an ADU be in Wayland, Massachusetts?
- No larger than half the main house's gross floor area or 900 sq ft, whichever is less.
- Does an ADU need parking or septic approval in Wayland, Massachusetts?
- It needs 1 dedicated parking space, none if within 0.5 miles of a transit or bus station, and written Board of Health septic approval before applying for the building permit.
- Can I rent my ADU on Airbnb in Wayland, Massachusetts?
- No. Short-term rental is not allowed, and there are no rentals under 31 consecutive days.
Massachusetts' statewide ADU law
Since February 2, 2025, the Affordable Homes Act (St. 2024, c. 150, §8) has protected one accessory dwelling unit (ADU) per lot in any zoning district that allows single-family homes (M.G.L. c. 40A, §3). Your town cannot ban it, require a special permit or other discretionary approval, or "unreasonably restrict" building or renting it.
What counts as a protected ADU:
- A self-contained unit with its own sleeping, cooking and bathroom facilities, on the same lot as the main home.
- No larger than 900 sq ft or half the main home's floor area, whichever is smaller.
- It can be attached or detached, and it needs a separate entrance that meets the building code.
What towns cannot require:
- That the owner live in the main home or the ADU.
- More than 1 extra parking space, or any extra space if the lot is within 0.5 miles of a subway, commuter rail, ferry or bus station.
- A minimum lot size, caps on the number of ADUs, or limits on who may live there (age, income, relationship).
What towns can still do: use reasonable site plan review, setback, height and bulk rules, require Title 5 septic compliance, and restrict or ban short-term rentals of ADUs. A second ADU on the same lot needs a special permit. State regulations at 760 CMR 71.00 (in effect since January 31, 2025) explain which rules count as unreasonable.
What the bylaw says
- §198-104.2 Definitions (Accessory Dwelling Unit), as amended, Accessory Dwelling Units zoning amendment (Planning Board article for 2025 ATM), p. 2
A self-contained housing unit, inclusive of sleeping, cooking and sanitary facilities on the same Lot as a Principal Dwelling, as defined by 760 CMR 71.02, subject to otherwise applicable dimensional and parking requirements, that: (i) maintains a separate entrance, either directly from the outside or through an entry shared with the Principal Dwelling sufficient to meet the requirements of the state building code for safe egress; (ii) is not larger in Gross Floor Area than 1/2 the Gross Floor Area of the Principal Dwelling or 900 square feet, whichever is smaller; and (iii) is subject to such additional restrictions as may be imposed by this Bylaw.
- §198-901.1.3.1 to 901.1.3.3 (new text), Accessory Dwelling Units zoning amendment (Planning Board article for 2025 ATM), p. 4
901.1.3.2. In addition to the minimum parking required for the Principal Dwelling, a minimum of one (1) dedicated parking space, not less than 10 feet by 20 feet, shall be provided for the occupant(s) of the ADU; provided, however, that for an ADU located 0.5 miles or less from a transit or bus station, no dedicated parking space shall be required. 901.1.3.3. An ADU may not be used as a short-term rental, meaning the ADU shall not be rented to a party for fewer than thirty-one (31) consecutive days consistent with G.L. c. 64G.
- §198-901.1.3.6 (new text), Accessory Dwelling Units zoning amendment (Planning Board article for 2025 ATM), p. 4
901.1.3.6. Prior to submitting a building permit application for an ADU, the applicant shall obtain written approval from the Board of Health that the septic system serving the Principal Dwelling and the proposed ADU is in compliance with the rules and regulations of the Board of Health in effect at the time of application, unless otherwise approved by Board of Health.
- §198-901.1.3.9 and 901.1.3.10 (new text), Accessory Dwelling Units zoning amendment (Planning Board article for 2025 ATM), p. 4
901.1.3.9. The maximum size of an ADU by-right is 1/2 of the existing GROSS FLOOR AREA as defined by 760 CMR 71.02 of the Principal Dwelling or 900 sq. ft., whichever is less. 901.1.3.10. The Planning Board may grant a Special Permit to allow more than one accessory dwelling unit in a detached structure on a lot after the Planning Board makes the special permit findings in accordance with Zoning Bylaw Section 198-203.
- Article 19, Motion 1 (2025 ATM), motion text, Accessory Dwelling Units zoning amendment (Planning Board article for 2025 ATM), p. 2
To see if the Town will vote to amend its Zoning Bylaws, Chapter 198, by amending §198- 104 - Definitions, §198-805 – Classification of accessory uses, §198-901 – Permitted uses, Attachment 3 – Table of Permitted Principal Uses by District and Attachment 5 – Table of Permitted Accessory Uses by District, to allow Accessory Dwelling Units (ADUs) as a use allowed by right in the Single Residence Zoning District to conform to the Massachusetts Affordable Homes Act by deleting text shown as strike through and inserting test shown as underlined and bolded, as follows, or take any other action relative thereto.
- §198-901.1.3.7 and 901.1.3.8 (new text), Accessory Dwelling Units zoning amendment (Planning Board article for 2025 ATM), p. 4
901.1.3.7. Application for a building permit or certificate of occupancy shall be made to the Building Commissioner. 901.1.3.8. No use or occupancy shall commence prior to the issuance of a certificate of occupancy by the Building Commissioner.