Plymouth

Plymouth County · Pop. 61,217

A

Plymouth has approved 34 of 42 ADU applications (81% approval rate) and has 5 of 10 bylaw provisions consistent with state law.

Some bylaw provisions aren’t yet consistent with state law, but permits are still being approved. State law overrides inconsistent local rules.
How active is your town?
5.6
per 10K residents2.8x state average
Plymouth
5.6
State avg
2.0

Based on 34 approved ADU applications and 61,217 residents

Permits

81%approval rateShare of 2025 applications approved in 2025
34 approved0 denied0 pending

42 applications since the ADU law took effect in Feb 2025

Talia Way
Issued
Conversion
Pine Mountain Dr
Issued
Conversion
Bearberry Path
Issued
Conversion
State Rd
Issued
Conversion
Billington Sea Rd
Issued
Conversion

Bylaw Consistency

5 / 10
provisions consistent with Chapter 150

Plymouth has 3 inconsistent provisions on the books that haven’t been reviewed by the AG. Owner-occupancy and lot frontage requirements mirror provisions struck down in other towns. These are preempted by state law but may still be applied locally.

Provision-by-provision analysis available

We've mapped 10 provisions in Plymouth against Chapter 150. See which specific bylaw sections appear inconsistent with state law.

See full compliance analysis

Cost Snapshot

Low
$125,000
Median
$325,000
High
$462,834

Based on 7 permitted ADU projects in Plymouth

Try the full cost estimator

ADU Impact on Housing Production

In 2024, Plymouth issued 293 total residential building permits. In the first year of the ADU law, 34 ADU permits were approved — equivalent to 11.6% of prior-year housing production.

2024 Building Permits
293
2025 ADU Approvals
34

Source: Census Bureau (2024) via UMass Donahue Institute; EOHLC ADU Survey (2025)

How Plymouth Compares

Next Steps

Sources: EOHLC ADU Survey 2025. Individual permit records from municipal building department. Population estimates from 2024 Census ACS.

Disclaimer: ADU Pulse provides data for informational purposes only. It does not constitute legal, financial, or construction advice.Bylaw consistency analysis reflects our interpretation of public records and may not reflect the most current local amendments.

See methodology for details on data collection, scoring, and consistency analysis.