Montgomery County, MD Noise from Specific Sources: Generator Noise (2026)
Key Facts
- Residential daytime limit
- 65 dBA
- Residential nighttime limit
- 55 dBA
- Daytime hours (weekdays)
- 7 a.m.-9 p.m.
- Enforcing agency
- Dept. of Environmental Protection
- First-offense civil penalty
- up to $500
Summary
Generators and motor-vehicle-powered devices must stay under the county's dBA noise limits or avoid creating a noise disturbance, county-wide.
(7) Operating power equipment mounted on a motor vehicle or operating other devices powered by a generator or a motor vehicle. (1996 L.M.C., ch. 32, § 1; 2011 L.M.C., ch. 7 , § 1.)
Editor’s note —See County Attorney Opinion dated 10/6/00 indicating that long-term parking on public streets is prohibited in certain circumstances, but not based on the size of the vehicle. See County Attorney Opinion dated 3/16/92 explaining that the Washington Metropolitan Area Transportation Authority (esp. Metrorail) is subject to the County’s noise control law, although an exemption may be obtained if it is in the public interest.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-90: Montgomery County Code contains legislation effective through May 7, 2026 | Zoning Updated Effective: April 13, 2026 | COMCOR Regulations effective as of July 1, 2026).
Full Breakdown
Montgomery County Code § 31B-5(c)(7) lists "operating power equipment mounted on a motor vehicle or operating other devices powered by a generator or a motor vehicle" as an example noise act that violates the Chapter if it exceeds the maximum allowable levels in § 31B-5(a) - 65 dBA daytime/55 dBA nighttime in residential noise areas, 67/62 dBA non-residential - or creates a "noise disturbance" under § 31B-5(b). Daytime runs 7 a.m.-9 p.m. weekdays (9 a.m.-9 p.m. weekends/holidays); all other hours are nighttime. Only agricultural field machinery and emergency-service equipment are exempt under § 31B-10(a); the Director may separately exempt routine residential power equipment used per manufacturer specs, but that exemption must be adopted by regulation. This is a Department of Environmental Protection program and applies within Montgomery County's incorporated municipalities too, unless a municipality has its own noise ordinance (Rockville, Gaithersburg, and Takoma Park each maintain separate codes).
Violations & Fines
Class A violation: up to $1,000 fine and 6 months jail criminally, or $500 civil penalty for a first offense and $750 for a repeat offense (Sec. 1-19); each day is a separate offense.
Frequently Asked Questions
Is running a generator in Montgomery County illegal?
Are portable generators exempt during power outages?
Sources & Official References
Other rules in Montgomery County
Compare Montgomery County to another location·View the Maryland noise from specific sources overview
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