ADUs Limited to Single-Family Dwellings

AG Disapproved

Falmouth, Barnstable County

Use & Occupancy

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What This Means for Your Project

The Attorney General has disapproved this provision as inconsistent with G.L. c. 40A §3. It is preempted by state law, though it may still appear in Falmouth's local code. Builders should cite the AG decision if this comes up during permitting.

State Law

G.L. c. 40A, § 3 and 760 CMR 71.00 allow Protected Use ADUs as of right on the same lot as any type of 'Principal Dwelling' — including two-family and multi-family structures — not just single-family homes.

Local Bylaw

Falmouth's bylaw defined ADUs in relation to 'single-family' dwellings and required ADUs to maintain the appearance of a 'single-family' residence (§§ 240-9.1A, 240-9.1B, 240-9.1D(a) and (b)).

Impact on Your Project

The Attorney General disapproved and deleted all references to 'single-family' in these sections because the state law allows ADUs on lots with any type of principal dwelling.

AG Decision

AG disapproved June 2, 2025 — all references to 'single-family' deleted from §§ 240-9.1A, 240-9.1B, 240-9.1D(a) and (b).

Sources

MGL c.40A §3 760 CMR 71.00 AG Decision — Falmouth (6/2/2025)Falmouth Bylaw § 240-9.1