Arvada, CO Noise from Specific Sources: Generator Noise (2026)

Section 38-34 defines a stationary noise source as any equipment or facility, fixed or movable, capable of emitting sound beyond the property boundary of the property on which it is used. A portable job-site unit, a standby unit on a pad and a commercial rooftop set all fit that definition. Once a generator counts as a stationary source, § 38-91 makes it unlawful to run it so that it exceeds the Table I limit for more than 90 percent of any measurement period, and the measurement lasts at least ten minutes.

Table I sets the numbers by use district. Residential and mixed-use land is held to 55 dB(A) from 7:00 a.m. to 9:00 p.m. and 50 dB(A) from 9:00 p.m. to 7:00 a.m. Commercial is 60 by day and 55 at night. Light industrial is 70 and 65. Heavy industrial is 75 around the clock. A planned unit development follows the table according to the predominant land use in its PUD plan. The reading is taken at the property boundary or at any point within the property affected by the noise, so a neighbor's yard counts as a measuring position. When a source is measured in more than one use district, § 38-93 applies the most restrictive district's limit at that district boundary.

Three add-on rules tighten the table. Section 38-94 covers fluctuating or intermittent noise, such as a unit that cycles with load: its tenth percentile level, the level exceeded for six minutes in one hour, cannot run more than 15 dB(A) above the ambient level measured while the source is quiet, and in residential land use categories it can never exceed 70 dB(A). Section 38-95 requires a pure tone, cyclically varying noise or repetitively impulsive noise to come in five dB(A) under the Table I limit, which is 50 dB(A) by day and 45 dB(A) at night in a residential district. Section 38-62(2) bars equipment used in construction activities in residential, commercial or mixed-use districts between 9:00 p.m. and 7:00 a.m.

The exceptions are narrow. Section 38-63 exempts noise caused in the performance of emergency work for the immediate safety, health or welfare of the community. Section 38-65 exempts a property owner's maintenance work done for safety and compliance with the City Code, but only while the noise is reasonable for the work and stays within the § 38-91 levels.