Montgomery County Code Chapter 31B sets specific decibel limits for Gaithersburg based on zoning and time of day. Residential zones are limited to 65 dBA daytime and 55 dBA nighttime. Commercial and industrial zones have higher thresholds. Enforcement uses calibrated sound-level meters at the receiving property line.
Montgomery County Code Chapter 31B establishes quantitative decibel standards applicable throughout Gaithersburg. Residential receiving properties have a maximum permissible level of 65 dBA during daytime (7 AM to 9 PM weekdays, 9 AM to 9 PM weekends) and 55 dBA during nighttime. Commercial receiving properties allow 67 dBA daytime and 62 dBA nighttime. Industrial receiving properties allow 75 dBA daytime and 70 dBA nighttime. Measurements are taken with calibrated Type II or better sound-level meters at the property line of the receiving (complaining) property using A-weighted slow response. Impulsive sounds and pure tones may receive a 5 dBA penalty adjustment. Ambient sound levels are considered — if existing ambient already exceeds the standard, the source must not increase levels by more than 5 dBA. Exemptions apply to emergency vehicles, permitted construction during allowed hours, agricultural operations, and permitted special events.
First offense carries a fine up to $500. Each subsequent offense may be fined up to $1,000. Each day of continued violation constitutes a separate offense.
See how other cities in Montgomery County handle decibel limits.
See how Gaithersburg's decibel limits rules stack up against other locations.
Quick Compare
Help us keep this page accurate. If you notice an error or outdated information, let us know.