St. Louis County, MO Noise Ordinances: Construction Hours (2026)
Construction hours in St. Louis County, MO, sometimes called construction noise rules or contractor work-hour ordinances, set when contractors can run power tools, hammers, and heavy equipment.
Key Facts
- Daytime hours (exempt)
- 7:00 a.m.–10:00 p.m.
- Nighttime hours (not exempt)
- 10:00 p.m.–7:00 a.m.
- Covered devices
- Compressors, pile drivers, bulldozers, cranes
- Enforcing agency
- Dept. of Public Health Director
Summary
Construction equipment is exempt from the county's noise limits only when run during daytime hours, 7:00 a.m. to 10:00 p.m.
(1)The operation of construction devices, with sound control devices equivalent to or better than the original equipment, used in construction activities during daytime hours. ... (9)Daytime hours: 7:00 o'clock a.m. to 10:00 o'clock p.m., prevailing local time. ... (18)Nighttime hours: 10:00 o'clock p.m., to 7:00 o'clock a.m., prevailing local time.
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
The Noise Control Code exempts construction devices from its decibel limits only while they're operated during daytime hours, defined as 7:00 a.m. to 10:00 p.m. Run the same equipment during nighttime hours (10:00 p.m. to 7:00 a.m.) and the exemption disappears, so the device must meet the chapter's ambient noise-level standards for the applicable land-use category, a bar heavy equipment like a pile driver, bulldozer or pneumatic hammer will almost always fail. Emergency repair work and public-facility construction/maintenance by government bodies are separately exempted regardless of hour.
Violations & Fines
Noise Control Code violations are enforced by the Director of the Department of Public Health, who issues a written notice of violation giving up to 60 days to abate (extendable with an acceptable abatement plan); continued nighttime construction noise exceeding Section 625.050's standards is a violation subject to the chapter's penalty provisions.
Frequently Asked Questions
Can construction crews run heavy equipment at night in St. Louis County?
Does the exemption cover all construction noise?
Sources & Official References
Other rules in St. Louis County
How St. Louis County compares: Cities with the Strictest Construction Hours·Compare St. Louis County to another location·View the Missouri noise ordinances overview
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