Decibel Limits: Cambridge vs Somerville
How do decibel limits rules compare between Cambridge, MA and Somerville, MA?
Somerville has fewer restrictions than Cambridge.
Cambridge, MA
Middlesex County
Cambridge enforces numerical decibel limits: 60 dBA day and 50 dBA night at residential receptors, with a 5 dBA penalty for tonal or impulsive sounds.
View full Cambridge 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 | Cambridge | Somerville |
|---|---|---|
| Day Limit | 60 dBA (7 AM to 10 PM) | - |
| Night Limit | 50 dBA (10 PM to 7 AM) | - |
| Tonal Penalty | Plus 5 dBA | - |
| Measurement | Type 2 meter at property line | - |
| Low-Frequency | Separate assessment available | - |
| 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.
Cambridge FAQ
What is a dBA versus dB?
dBA is A-weighted decibels, which adjusts for human hearing sensitivity. Cambridge uses dBA for most limits, with special handling for low-frequency sound.
How loud is 50 dBA?
About the level of a quiet refrigerator or light rainfall, roughly 15 feet from a normal conversation.
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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