10 county-level rules, plus city-specific rules for 2 cities in Jefferson County, Colorado.
Verified from official government sources
In unincorporated Jefferson County, noise from a residential property line may not exceed 55 dB(A) from 7:00 a.m. to 7:00 p.m. or 50 dB(A) from 7:00 p.m. to 7:00 a.m. Nighttime is the effective quiet period.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, D.3
Sound from a non-vehicular source located in a residential zone, shall not exceed the following limits: 7:00 A.M. until 7:00 P.M.: 55 dB(A); 7:00 P.M. until 7:00 A.M. of the same day of the following day: 50 dB(A).
Construction in residential zones may reach 80 dB(A) from 7:00 a.m. to 7:00 p.m. and 75 dB(A) from 7:00 p.m. to 7:00 a.m., for the period allowed by the construction permit or a reasonable completion time.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, D.5
Construction projects in residential zones shall be subject to the following permissible noise levels... 7:00 A.M. until 7:00 P.M.: 80 dB(A); 7:00 P.M. until 7:00 A.M. of the same day of the following day: 75 dB(A).
Jefferson County's noise decibel rules expressly exempt "the sound made by animals," so barking is not a decibel violation. Persistent barking is handled instead through Animal Control's nuisance and disturbance provisions.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, B.2.i
Exceptions apply to: ... i. The sound made by animals.
Jefferson County has no leaf-blower-specific rule. A leaf blower is treated as any non-vehicular residential noise source, so it must not exceed 55 dB(A) (7 a.m.-7 p.m.) or 50 dB(A) (7 p.m.-7 a.m.) at 25 feet from a property line.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, B.1
No person shall operate any type of vehicle, machine, or device, or carry on any activity... which makes sound in excess of the level specified in the Permissive Noise Levels Section.
Amplified music is regulated as any noise-making "activity." In a residential zone it may not exceed 55 dB(A) (day) or 50 dB(A) (night) at 25 feet from a property line, with a lower cap for shrill or pulsing sound.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, B.1
No person shall operate any type of vehicle, machine, or device, or carry on any activity, or promote or facilitate the carrying on of any activity which makes sound in excess of the level specified in the Permissive Noise Levels Section.
Neither Jefferson County nor Colorado's noise statute regulates aircraft noise. CRS 25-12-103(4) states the article does not apply to aircraft, which are governed by federal (FAA) law. Rocky Mountain Metropolitan Airport handles local complaints.
CRS 25-12-103(4)
This article is not intended to apply to the operation of aircraft or to other activities which are subject to federal law with respect to noise control.
Industrial-zone noise may reach 80 dB(A) (7 a.m.-7 p.m.) and 75 dB(A) (7 p.m.-7 a.m.) at a property line under CRS 25-12-103. Light-industrial zones are held to 70/65 dB(A).
CRS 25-12-103(1)
Zone Maximum Sound Level dB(A) 7 am to 7 pm / 7pm to 7 am: ... Light Industrial 70 / 65; Industrial 80 / 75.
Colorado statute CRS 25-12-103 caps noise at a property line by zone: 55/50 dB(A) residential, 60/55 commercial, 70/65 light industrial, and 80/75 industrial (day/night). Jefferson County mirrors these limits.
CRS 25-12-103(1)
Sound levels of noise radiating from a property line at a distance of twenty-five feet or more therefrom in excess of the db(A) established... shall constitute prima facie evidence that such noise is a public nuisance: Residential 55/50; Commercial 60/55; Light Industrial 70/65; Industrial 80/75.
Outdoor live or recorded music is limited by the same residential caps: 55 dB(A) (day) and 50 dB(A) (night) at 25 feet from a property line. Non-profit and government cultural events are exempt.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, B.2.c
Exceptions apply to: ... c. The use of property by this state, any political subdivision of this state, or any other entity not organized for profit... for the purpose of promoting, producing, or holding cultural, entertainment, athletic, or patriotic events, including... concerts, music festivals, and fireworks displays.
Every vehicle in unincorporated Jefferson County must have a working, unmodified muffler. On roads posted 35 mph or less, most vehicles may not exceed 80 dB(A) (measured 50 feet from the lane center); cutoffs and bypasses are prohibited.
Jefferson County Noise Abatement Policy, Part 3, Ch. 1, Sec. 1, E.1, E.3
No person shall operate anywhere in unincorporated Jefferson County any vehicle that is not equipped with a muffler in constant operation... any vehicle having a muffler that has been equipped or modified with a cutoff, bypass, or any similar device or modification.
2 cities in Jefferson County have their own noise ordinances rules. Each link goes to that city's dedicated page with code citations.
See every category we cover for Jefferson County — parking, noise, fences, fires, animals, pools, and more.
Jefferson County Ordinance Hub →