St. Louis County, MO Noise Ordinances: Decibel Limits (2026)
Key Facts
- Residential daytime cap
- 55 dB(A) continuous
- Residential nighttime cap
- 50 dB(A) continuous
- Nighttime hours
- 10 p.m. to 7 a.m.
- Discrete tone/impulsive noise
- 5 dB lower limit
- Governing chapter
- Ch. 625, Noise Control Code
Summary
St. Louis County caps stationary noise sources at set dB(A) levels by land-use zone and time of day, with lower nighttime and residential thresholds.
No person shall operate or permit to be operated and stationary noise source which emits noise...exceeds the levels set forth in Table I below...A. Residential Land Use Category Daytime Hours Tn* (dB(A))** 60 55 or less 30 56-58 15 59-61 8 62-64 4 65-67 2 68-70 0 71 or greater...Nighttime Hours 60 50 or less 30 51-53 15 54-56 8 57-59 4 60-62 2 63-65 0 66 or greater
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 85 | Traffic: Supplement 80).
Full Breakdown
Under the Noise Control Code, no one may operate a stationary noise source that exceeds the decibel limits in Table I when measured from outside the source property's boundary. Residential zones cap continuous noise at 55 dB(A) daytime and 50 dB(A) nighttime, with brief spikes allowed up to 71 dB(A) daytime and 66 dB(A) nighttime for zero minutes. Commercial, light-industrial, and heavy-industrial zones get progressively higher allowances. Discrete tones and impulsive noise get an added 5 dB reduction in the allowed ceiling, and the code covers unincorporated areas plus incorporated cities under 75,000 population without their own equivalent noise program.
Violations & Fines
Exceeding Table I's dB(A) ceiling for the applicable zone, time period, and duration is a violation; enforcement runs through the Department of Community Health and Medical Care and the Appeal Board process set out in the chapter.
Frequently Asked Questions
What's the loudest a neighbor's equipment can legally be at night in a residential area?
Does this decibel table apply inside incorporated cities too?
Sources & Official References
Other rules in St. Louis County
Compare St. Louis County to another location·View the Missouri noise ordinances overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.