St. Louis County, MO Noise Ordinances: Aircraft Noise (2026)
Key Facts
- Aircraft covered by definition
- §625.020(26) "stationary noise source" includes aircraft
- Exempt
- In-flight operation & pre-takeoff run-up (any hour)
- Regulated
- Maintenance/test run-up, 10 p.m.-7 a.m.
- Nighttime hours defined
- 10:00 p.m. to 7:00 a.m. (§625.020(18))
- Max penalty
- $1,000 fine or 1 year jail, per day
Summary
St. Louis County's Noise Control Code exempts an aircraft's actual flight and pre-takeoff engine run-up from its decibel limits, but Section 625.070(7) pulls ground maintenance and test run-ups back under the Code at night: aircraft engines run for maintenance or testing, mounted or not, must meet the Table I nighttime noise limits between 10 p.m. and 7 a.m.
(26)Stationary noise source: Any equipment, motor vehicle, aircraft, or facility, fixed or movable, capable of emitting audible sound. ... (7)The inflight operation of aircraft, including the pre-takeoff run-up of aircraft engines; provided, however, with the exception of the pre-takeoff run-up of aircraft engines, the provisions of this chapter shall apply to the run-up of aircraft engines, mounted or unmounted, for maintenance or test purposes during nighttime hours.
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
020(26) defines a "stationary noise source" to expressly include "any equipment, motor vehicle, aircraft, or facility, fixed or movable, capable of emitting audible sound," bringing aircraft on the ground within the Noise Control Code's reach. m. , whether the engine is still mounted on the airframe or removed for bench testing, must keep the noise at or below the applicable Table I limit measured at the property boundary, the same numeric standard the Code applies to any other stationary commercial or industrial noise source. Daytime maintenance run-ups and any pre-takeoff run-up at any hour remain outside the Code entirely, and in-flight noise is never covered no matter the hour. The Code applies countywide in unincorporated St. 030.
Violations & Fines
A nighttime aircraft engine run-up for maintenance or testing that exceeds the Table I decibel limit at the property boundary violates the Noise Control Code through Section 625.070(7)'s carve-out and Section 625.050's standards. Section 625.180 sets the penalty for any violation of the Code: a fine of up to $1,000, up to one year in the county jail, or both, with each day of violation a separate offense, and the County Counselor may also seek a court order requiring compliance.
Frequently Asked Questions
Can an airport run aircraft engines at any hour without violating the noise code?
Does the Noise Control Code apply to aircraft at all?
What's the penalty for a nighttime run-up that's too loud?
Does this rule cover every city in St. Louis County?
Sources & Official References
Other rules in St. Louis County
Compare St. Louis County to another location·View the Missouri noise ordinances overview
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