Noise Ordinances in Jefferson County, MO (2026)
5 rules for unincorporated Jefferson County, Missouri.
Verified from official government sources
Construction Hours
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.
Construction Noise Rules in Jefferson County
Some RestrictionsJefferson County, MO UDO § 400.220.A.1 and A.3 [Zoning Order § 2.020, 4-2-2008]
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. ...
Barking Dogs
Jefferson County bars dogs kept in the unincorporated area from howling or barking continually beyond the property line: more than 15 minutes between 10 p.m. and 8 a.m., more than 30 minutes between 8 a.m. and 10 p.m., or more than five shorter episodes in a 10-day span, enforced by Animal Control and the Municipal Prosecutor.
Jefferson County Barking Dog Time Limits
Some RestrictionsJefferson County, MO Code of Ordinances § 205.125(B)
It shall constitute a violation of this Section if the howling or barking occurs continually and is audible beyond the property line of the premises on which the dog is located: 1. For more than fifteen (15) minutes between the hours of 10:00 P.M. and 8:00 A.M.; or 2. For more than thirty (30) minutes between the hours of 8:00 A.M. and 10:00 P.M.; or 3. For a shorter duration than cited above, ...
Amplified Music & Outdoor Sound
Jefferson County presumes music, speech, or noise disturbs the peace once it is plainly audible more than fifty feet from its source in the unincorporated area. Radios, music players and instruments played to disturb a reasonable person are prohibited, with a carve-out for lawful concerts and farm or business operations.
Jefferson County's 50-Foot Audible Noise Standard
Some RestrictionsJefferson County, MO Code of Ordinances §205.120(A)(1), (B)
A. It shall be unlawful to create a peace disturbance in the unincorporated area of Jefferson County, Missouri, by: 1. Playing any radio, music player, television, audio system, or musical instrument in a manner or at a volume that disturbs the peace of any other reasonable person; except that nothing herein shall be construed to prohibit an otherwise lawful public concert or public performance...
Decibel Limits
Jefferson County's Unified Development Ordinance caps data center noise at 55 dBA in the daytime and 50 dBA overnight when the equipment sits near a home, school, church or farm with a dwelling. UDO Section 400.3720 also limits low-frequency sound to 65 dBC by day and 60 dBC at night, and lets the limit rise 5 decibels next to non-residential land.
Jefferson County Data Center Noise Decibel Limits
Significant RestrictionsJefferson County, MO UDO § 400.3720
B. Maximum allowable sound limits from all equipment shall not exceed the following as measured at property lines: 1. Daytime (7:00 A.M. to 10:00 P.M.). a. Maximum Limit: 55 dBA. b. Maximum Low-Frequency Limit: 65 dBC. 2. Nighttime (10:00 P.M. to 7:00 A.M.). a. Maximum Limit: Fifty (50) dBA. b. Maximum Low-Frequency Limit: Sixty (60) dBC. 3. The above limits apply if the adjoining property(s) a...
Vehicle Noise
Jefferson County's Traffic Code bans muffler cutouts and requires every motor vehicle on unincorporated county roads to run a muffler quiet enough to match a modern passenger car's exhaust. Drivers also can't make excessive noise from a motor, signaling device, tires or an improperly loaded cargo, and engine compression brakes are barred in posted zones.
Jefferson County Bans Loud Mufflers, Engine Brakes
Some RestrictionsJefferson County, MO Code of Ordinances §§ 340.100, 340.110
Muffler cutouts shall not be used and no vehicle shall be driven in such manner or condition that excessive and unnecessary noises shall be made by its machinery, motor, signaling device, or other parts, or by any improperly loaded cargo. The motors of all motor vehicles shall be fitted with properly attached mufflers of such capacity or construction as to quiet the maximum possible exhaust noi...
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