Jefferson County, MO Noise Ordinances: Construction Hours (2026)
Construction hours in Jefferson 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
- Governing section
- UDO § 400.220.A.1 and A.3
- Exempt window
- 7:00 A.M. to 7:00 P.M. daily
- Outside window
- District decibel/vibration standard applies
- Noise measurement
- dB(A), A-weighted filter, fast response for impact noise
- Vibration measurement
- Particle velocity, three-component instrument
- Adopted
- Zoning Order § 2.020, effective 4-2-2008
Summary
Jefferson County's UDO exempts temporary construction noise and vibration from its quantitative performance standards only between 7:00 A.M. and 7:00 P.M. Outside that twelve-hour window, construction activity is measured against the same decibel and vibration limits that apply to any other use in the zoning district.
Unless specifically indicated to the contrary in the zoning district regulations, noise resulting from temporary construction activity that occurs between 7:00 A.M. and 7:00 P.M. shall be exempt from the indicated standard. ... Unless specifically indicated to the contrary in the zoning district regulations, vibration resulting from temporary construction activity that occurs between 7:00 A.M. and 7:00 P.M. shall be exempt from the indicated standard.
Full Breakdown
220 sets the County's quantitative performance standards for noise, smoke, vibration and glare, the numeric limits zoning districts use to judge whether a use is compatible with its surroundings. window. Read together, the two exemptions mean a contractor pouring concrete, operating heavy equipment, or driving pilings on an active job site inside that daytime window does not have to meet the district's ordinary decibel or particle-velocity ceiling. , the exemption disappears and the site is judged against the same quantitative standard as any other use in that zoning district, with compliance measured at the property line or another designated location using the calibrated instruments the section specifies.
The exemption applies only to activity that is 'temporary,' tied to active construction, not to a permanently installed noise source on a finished site, and only where a specific zoning district regulation does not already say otherwise.
Violations & Fines
Construction noise or vibration measured outside the 7:00 A.M. to 7:00 P.M. exemption window, or that exceeds the district's decibel or particle-velocity standard once the exemption no longer applies, is a violation of the UDO's performance standards enforceable under Section 400.140: a misdemeanor punishable by a fine up to $1,000, up to one year imprisonment, or both, with each day of continued violation a separate offense, plus injunctive relief the County may seek in Circuit or Municipal Court.
Frequently Asked Questions
Can a contractor legally run heavy equipment at 6 A.M. in Jefferson County?
Does the 7 A.M. to 7 P.M. exemption cover every kind of noise on a job site?
Where is construction noise actually measured under this rule?
Sources & Official References
Other rules in Jefferson County
How Jefferson County compares: Cities with the Strictest Construction Hours·Compare Jefferson County to another location·View the Missouri noise ordinances overview
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