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Noise Control: Overview

Just as litter degrades the landscape of the community, noise degrades the soundscape. The U.S. Census Bureau's "Surveys of Neighborhood Problems," conducted over the past three decades, has consistently placed noise among the top four issues of concern. Noise can interfere with normal residential and business activities. Persistent exposure can result in psychological stress and at high enough levels it can damage hearing.

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What Constitutes a Noise Violation?

A noise disturbance, as defined by the Montgomery County Noise Ordinance, is any sound that is:

  • Unpleasant, annoying, offensive, loud, or obnoxious
  • Unusual for the time of day or location where it is produced or heard
  • Detrimental to the health, comfort, or safety of any individual or to the reasonable enjoyment of property or the lawful conduct of business because of the loudness

Under the ordinance, it is unlawful to create a noise disturbance anywhere during quiet hours, including multifamily buildings and townhouses. The nuisance provision prohibits some noise disturbances anywhere at any time.

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How Is Noise Measured?

The standard unit by which sound is measured is the decibel (dB), a relative measure of sound intensity. Decibels are calculated on a logarithmic scale (meaning that a measure of 40 dB is 10 times greater than one of 30 dB). Some examples of typical situations and their corresponding decibel levels are:

Situation Level of Intensity (dBA*)
Whispering in an indoor location 20 dBA
Average office environment 50 dBA
Typical conversation speech 50 - 70 dBA
Car horn (at 10 feet) 100 dBA
Hard rock band (indoors) 120 dBA
Physical pain threshold 130 dBA
Jet engine 140 dBA

* Note: The ordinance uses an A-weighted scale, measured in A-weighted decibels (dBA). A-weighting is an electronic approximation.


Intensity vs. Loudness

Decibels are a measure of sound intensity—the pressure of sound waves on the human ear. They provide a standardized, objective unit of measure and differ from a measure of the perceived "loudness" of a sound. Loudness is a subjective measure because different people have different levels of hearing and don't experience sound in the same way. Someone who is hard of hearing, for example, might not perceive a jackhammer as loud while someone with excellent hearing could be disturbed by the same noise. Both people, however, would experience the same level of sound intensity.


Be Aware! When continuous exposure to sound reaches 85 dBA (as in a factory), there is a great risk of permanent hearing loss.

Learn more about noise control in Montgomery County

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Last edited: 7/5/2012