Decibel Limits: Ayer vs Somerville
How do decibel limits rules compare between Ayer, MA and Somerville, MA?
Ayer and Somerville have similar restriction levels.
Ayer, MA
Middlesex County
Middlesex County follows Massachusetts 310 CMR 7.10 which caps sound at 10 dBA over ambient at property lines. Many cities add hard numeric limits of 65 dBA day / 55 dBA night in residential zones.
View full Ayer rules →Somerville, MA
Middlesex County
Somerville uses both plainly-audible standards and numeric decibel caps for specific sources, typically 65 to 75 dBA during day and 55 to 65 dBA at night measured at residential property lines.
View full Somerville rules →Key Facts Comparison
| Fact | Ayer | Somerville |
|---|---|---|
| State floor | 10 dBA over ambient | - |
| Residential day | 60-65 dBA typical | - |
| Residential night | 50-55 dBA typical | - |
| Commercial | 70 dBA typical | - |
| Measurement | At property line, Type 2 meter | - |
| Residential day limit | - | Approximately 65 dBA |
| Residential night limit | - | Approximately 55 dBA |
| Commercial day limit | - | 70 to 75 dBA |
| Leaf blower cap | - | 65 dBA at 50 feet |
| Measurement by | - | ISD and Somerville Police |
Highlighted rows indicate differences between cities.
Ayer FAQ
What is the quietest limit in Middlesex County?
Cambridge applies 50 dBA nighttime in residential zones, among the strictest in the county.
Does the state rule trump my town?
No, but it is the minimum. Cities can set stricter limits but cannot exceed the state 10-dBA-over-ambient cap.
Somerville FAQ
Do the limits apply to HVAC units?
Yes. Fixed mechanical equipment is among the most-measured sources and often requires acoustic enclosures to meet nighttime limits.
Is the plainly-audible test subjective?
Somewhat, but it is legally valid and often used as the first enforcement step before a formal dBA measurement.
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