Declaration of Policy.
A. 
The city council enacts this legislation for the sole purpose of securing and promoting the public health, comfort, safety and welfare of its residents.
B. 
In order to control unnecessary, excessive and annoying noises in the city of Brentwood, it is declared to be the policy of the city to prohibit noise, which is detrimental to the health and welfare of its residents.
C. 
It shall be the policy of the city of Brentwood to maintain and preserve the quiet atmosphere of the city, and to implement programs and enact legislation consistent with the objectives and goals set forth in the noise element of the general plan and aimed at retaining noise levels throughout the city acceptable values established in the general plan.
(Ord. 696 § 2, 2002)
The following words, phrases and terms, as used in this article, shall have the meanings as indicated:
"Ambient noise"
means the composite of all noise from sources near and far, excluding the alleged intrusive noise source. The ambient noise level (or ambient level) is the normal or existing level of environmental noise at a given location.
"A weighted sound level"
means the sound level as measured on a sound level meter using the "A" weighting network. The level so read is designated in units of dBA.
"Construction"
means any site preparation, assembly, erection, substantial repair, alteration, or similar action, for or of public or private right-of-way, structures, utilities or similar property.
"Decibel"
means a unit for measuring the amplitude of a sound. equal to twenty times the logarithm to the base of ten of the ratio of the pressure of the sound measured to the reference pressure, which is twenty microPascals.
"Designated noise zone"
means a zone consisting of real property corresponding to the city of Brentwood's official zoning map and the noise element of the city's general plan, as it may be amended from time to time.
"Emergency work"
means work made necessary to protect, provide or restore safe conditions in the community or for the citizenry, or work required to protect persons or property from an imminent exposure to danger, or work by private or public utilities when restoring utility service.
"Fixed noise source"
means a stationary device, which creates sounds while in a fixed or stationary position, including, but not limited to, industrial and commercial machinery and equipment, pumps, fan compressors, generators, air-conditioners and refrigeration equipment.
"Impulsive noise"
means a sound of short duration, and lasting less than one second with an abrupt onset and rapid delay.
"Intrusive noise"
means that alleged offensive noise, which intrudes over and above the ambient noise for the receiving property.
"Leq"
is the energy equivalent level, defined as the average sound level on the basis of sound energy (or sound pressure squared). The Leq is a dosage type measured and the basis for the descriptors used in current standards, such as the twenty-four hour CNEL used by the state of California.
"Mobile noise source"
means a noise source other than a fixed noise source. Noise level (sound level) means the "A" weighted sound level.
"Noise level (sound level)"
means the "A" weighted sound level.
"Noise level limit"
means the maximum noise level acceptable under this article for the stated time period.
"Noise sensitive property"
means any property, regardless of zone, so designated in the noise element of the city's general plan. Noise sensitive properties include schools, hospitals, convalescent care, boarding and rest homes.
"Person"
means any individual, firm, association, partnership, joint venture or corporation.
"Public right-of-way"
means that area dedicated or subject to an easement for public use for vehicles and/or pedestrian travel including, but not limited to, streets, alleyways and sidewalks.
"Pure tone"
means any sound, which can be judged as audible as a single frequency or set of single frequencies. For the purpose of this chapter, a pure tone shall exist if the one-third octave band sound pressure level in the band with the tone exceeds the arithmetic average of the sound pressure levels of the two contiguous one-third octave band as follows: by 5 dB for band frequencies between 160 and 400 Hz; or by 15 dB for band frequencies less than or equal to 125 Hz.
"Receiving property"
means the property for which the intrusive noise is alleged to be offensive.
"Sound amplifying equipment"
means any machine or device for the amplification of the human voice, music or other sound regardless of location. "Sound amplifying equipment" as used in this article, shall not include warning devices on authorized emergency vehicle or horns or other warning devices on any vehicles used only for traffic safety purposes.
"Sound level meter"
means an instrument, including a microphone, an amplifier, an output meter, and frequency weighting networks for measurement of sound levels, which satisfies the requirements pertinent for sound level meters in American National Standard Institute specifications for sound level meters, Section 1.4-1971, or the most recent revision therefor, for type S-2A sound meters.
"Supplementary definition of technical terms."
Definitions of technical terms not defined herein shall be obtained from American Standard Acoustical Terminology, Section 1-1-1971 or the most recent revision thereof.
(Ord. 696 § 2, 2002)
A. 
Assignment of Noise Zones. Receiving properties are assigned to designated noise zones as follows:
1. 
Designated noise zone I—residential properties;
2. 
Designated noise zone II—commercial properties;
3. 
Designated noise zone III—industrial properties.
B. 
Exterior Noise Levels.
1. 
Noise zone exterior noise levels. The following exterior noise levels, unless otherwise specifically indicated, shall apply to all receiving properties within a designated noise zone for the purpose of establishing noise level limits in subsection 9.32.030(B):
Zones #'s
Designated Zone
Time Interval
Exterior Noise Levels
Zone I
Residential
7:00 a.m.-10:00 p.m.
60
10:00 p.m.-7:00 a.m.
45
Zone II
Commercial
7:00 a.m. -10:00 p.m.
60
10:00 p.m. -7:00 a.m.
45
Zone III
Industrial
7:00 a.m. -10:00 p.m.
65
10:00 p.m. -7:00 a.m.
60
2. 
Noise level limits. Unless otherwise provided in this article, no person shall operate or cause to be operated any source of sound at any location within the city, or allow the creation of any noise on property owned, leased, occupied or otherwise controlled by such person which causes the noise level when measured on any receiving property to exceed the following noise level limits:
a. 
The exterior noise levels for that land use, as specified in subsection 9.32.030(B)(1), for a total of more than thirty minutes in any consecutive sixty minutes;
b. 
The exterior noise levels plus 5 dB for a total period of more than fifteen minutes in any consecutive sixty minutes;
c. 
The exterior noise levels plus 10 dB for a total period of more than five minutes in any consecutive sixty minutes; or
d. 
The exterior noise levels plus 15 dB for a total period of more than one minute in any consecutive sixty minutes; or
e. 
The exterior noise levels plus 20 dB for any time.
3. 
Ambient noise level in excess of noise level limits. If the ambient noise level exceeds that permissible for any of the noise level limits in subsections 9.32.030(B)(2)(a), (b), (c) and (d), the noise level limit shall be increased in 5 dB increments as appropriate to encompass or reflect said ambient noise level. In the event the ambient noise level exceeds the noise level limit in subsection 9.32.030(B)(2)(e) this limit shall be increased to the maximum ambient noise level.
4. 
Boundary between different zones. If the measurement location is on a boundary between two different designated noise zones, the lower noise level limit applicable to the two zones shall apply.
5. 
Content of intrusive noise. In the event the intrusive noise is judged by the enforcing officer to contain a steady, audible, pure tone such as a whine, screech or hum, or is an impulsive noise, or is a repetitive noise exceeding one second in duration or contains music or speech, the noise level limits set forth in subsection 9.32.030(B)(2), shall be reduced by 5 dB.
C. 
Interior Noise Levels.
1. 
Noise zone interior noise levels. The following interior noise levels, unless otherwise specifically indicated, shall apply within all receiving multifamily residential units within noise zone I and II for the purpose of establishing noise level limits in subsection 9.32.030(C)(2):
 
Time Interval
Interior Noise
Multi-family residential
10:00 p.m. to 7:00 a.m.
40
7:00 a.m. to 10:00 a.m.
45
2. 
Residential unit, interior noise level limits. No person shall operate or cause to be operated within a multifamily residential unit, any source of sound or allow the creation of any noise which causes the noise level when measured inside a neighboring receiving residential unit whether adjacent or not, to exceed the following noise level limits:
a. 
The interior noise levels as specified in subsection 9.32.030(C)(1) for a total period of more than five minutes in any consecutive sixty minutes;
b. 
The interior noise levels, plus 5 dB for a total period of more than one minute in any consecutive sixty minutes; or
c. 
The interior noise levels, plus 10 dB for any period of time.
3. 
Ambient noise level in excess of noise level limits. If the ambient noise level exceeds that permissible for noise level limits in subsection 9.32.030(C)(2)(a) or (b), the limit shall be increased in 5 dB increments as appropriate to reflect said ambient noise level. In the event the ambient noise level exceeds the noise level limit in subsection 9.32.030(C)(2)(c), this limit shall be increased to the maximum ambient noise level.
4. 
Content of intrusive noise. In the event the intrusive noise is judged by the enforcing officer to contain a steady, audible, pure tone such as a whine, screech or hum, or is an impulsive noise or a repetitive noise exceeding one second in duration, or contains music or human voices, the noise level limits set forth in subsection 9.32.030(C)(2), shall be reduced by 5 dB.
(Ord. 696 § 2, 2002)
A. 
Use of "A" weighted sound level. Any sound levels measured pursuant to the provisions of this article shall be "A" weighted sound levels, measured with a sound level meter using the "A" weighting and slow response, except for impulsive noise, for which the fast response shall be used. The microphone should whenever possible be located four to five feet above the ground and ten feet or more from the nearest reflective surface.
B. 
Exterior Noise Measurement. The microphone shall not be less than five feet above ground, at least five feet distance from walls or other large reflecting surfaces, and shall be protected from the effects of wind noise by the appropriate windscreens. In cases when the microphone must be located within ten feet of walls or similar large reflecting surfaces, the actual measured distance and orientation of sources, microphone and reflecting surfaces shall be noted and recorded. In no case shall a noise measurement be taken at five feet of the noise source.
C. 
Interior Noise Measurement. Interior noise measurements shall be made within the affected residential unit. The measurements should whenever possible be made at a point at least four feet from the wall, ceiling or floor nearest the noise source with windows opened or closed at the discretion of the resident.
D. 
Calibration Prior to Measurement. Calibration of the measurement equipment, utilizing an acoustic calibrator, shall be performed prior to making any noise measurements.
E. 
Ambient Noise Level Measurement. When ambient noise levels are measured, these levels should be measured whenever possible at a location and time of day comparable to that used for measuring the intrusive noise.
F. 
Method for Sound Level Measurement. The director of community development may, from time to time, cause preparation of a noise control enforcement manual to assist in implementing the purpose of this article.
(Ord. 696 § 2, 2002)
A. 
Grading, Site Improvement, Infrastructure Improvements and Outside Heavy Construction. All operation of power construction equipment or any other construction device that creates noise in excess of the noise level limits of this article, and all performance of any outside construction work, including, but not limited to, grading and trenching, that creates noise in excess of the noise level limits of this article shall be limited to the following hours: Monday through Friday from seven a.m. until three-thirty p.m., or until five-thirty p.m. with the express written approval of the city engineer or designee. No such work shall be performed on Saturday or Sunday or city holidays, except that such work may be performed on Saturday between eight a.m. and five p.m. with the express written approval of the city engineer or designee.
1. 
Home repairs and routine maintenance of personal property are not considered construction.
2. 
Construction activities within city right-of-way, such as road work or installation of drainage facilities, may be performed outside of the specified work hours of this subsection A, including overnight work, with the express written approval of the city engineer or designee.
3. 
The planning commission and city council may impose more restrictive hours of construction upon any projects involving construction activity by adding appropriate conditions to the city's approval of subdivisions, planned development permits, conditional use permits, variances and other projects.
4. 
The performance of emergency work is exempt from the provisions of this subsection A. The city engineer may require the production of evidence after the fact that an emergency existed that would constitute a hazard to persons or property and may cite the responsible parties for a violation of this section if no such evidence is produced.
B. 
Outside Carpentry Construction. No person in a residential zone shall operate or permit the operation of any mechanically powered saw, sander, drill, grinder or similar tools, so as to create any noise which exceeds the noise level limits of this article, except during the following hours: Monday through Friday from seven a.m. until seven p.m. and Saturday from nine a.m. to five p.m.
1. 
No work described in this subsection B may performed on Sunday or any city holiday or on Monday through Saturday outside of the hours specified above unless all such work is conducted within a completely enclosed structure.
2. 
Home repairs, lawn mowing, gardening and routine maintenance of personal property is not considered construction.
C. 
Vehicles Off Public Right-of-Way. No person shall operate or cause to be operated any motor vehicle, off a right-of-way, in such a manner that the sound levels emitted there from exceed the noise level limits of this article.
D. 
Vehicle Repair and Testing. No person shall repair, rebuild, modify or test any motor vehicle in such a manner as to create any noise, which exceeds the noise level limits of this article.
(Ord. 986 § 2, 2017)
A. 
Environmental Factors. The environmental factors which may be considered in determining whether a violation of provisions exists includes, but is not limited to, the following:
1. 
The sound level of the intrusive noise;
2. 
The sound level of the ambient noise;
3. 
The proximity of the noise to residential sleeping facilities;
4. 
The nature and zoning of the area from which the noise emanates;
5. 
The number of persons affected by the alleged intrusive noise;
6. 
The time of day or night the noise occurs;
7. 
The duration of the noise and its tonal content;
8. 
Whether the noise is continuous, recurrent, or intermittent.
(Ord. 696 § 2, 2002)
A. 
The emission of sound for the purpose of alerting persons to the existence of an actual emergency or the emission of sound in the performance of emergency work shall not be subject to the provisions of this article.
B. 
Warning devices necessary for the protection of public safety, as, for example, police and fire and ambulance sirens, including the testing of such devices, shall not be subject to the provisions of this chapter.
C. 
Activities conducted on public playgrounds and public or private school grounds including, but not limited to, school athletic and school entertainment events, are exempt from the provisions of this article. Sounds emanating from regularly scheduled athletic events at city parks.
D. 
Sounds or noise from lawful fireworks.
E. 
City authorized parades, street fairs, festivals or celebrations.
F. 
Construction activity or garbage collection performed by an agency of government, provided that all equipment is operated in accordance with manufacturer's specifications and is equipped with all noise reducing equipment in proper condition.
G. 
In-home private parties are exempt from obtaining a temporary use permit for activities, however they are not exempt from the noise standards within this chapter.
H. 
All agricultural and farming activities.
(Ord. 696 § 2, 2002)
A. 
The city of Brentwood community development department may grant a temporary use permit, which allows noncompliance with the limitations prescribed in this chapter for the purpose of sound activities of short duration.
B. 
Permits may be granted upon application and when said application is in compliance with the provisions of subsection C.
C. 
The following factors shall be considered in the initial investigation in order to determine whether granting of the permit in a condition injurious to health or safety:
1. 
Distance of proposed activities from any residential or noise sensitive zone;
2. 
Number of amplification devices, if any, to be used in the proposed activities;
3. 
Sound level capability of amplification devices and anticipated sound level;
4. 
Anticipated direction of amplification devices;
5. 
Anticipated duration of proposed activities;
6. 
Whether the activity will be held within or outside of structure;
7. 
Time of day and day of week of proposed activities;
8. 
Submit proposed activity plan to the police department for review and approval;
9. 
Any other consideration deemed necessary by the community development department.
D. 
The permit, if issued, shall specify the place, duration, and any restrictions appropriate to the proposed site of the activities.
E. 
Permits must be displayed and available for review by police or code enforcement officer upon request.
F. 
Issued permits will be surrendered to any police or code enforcement officer or other city official upon request when the restrictions of the permit have been violated.
G. 
Reapplication for a permit may be denied upon evidence of a complaint by a resident in the locality of the permitted activity or if an applicant has in the past been required to surrender a permit as described in subsection F.
H. 
A permit may be issued for more than one occasion of activity. However, the time of such activity must be indicated on the application and cannot be for more than four occasions or in excess of a six-week period.
I. 
If the city denies the temporary use permit the applicant may appeal the decision pursuant to Chapter 17.880 (Appeal) of the city of Brentwood's Municipal Code.
(Ord. 696 § 2, 2002)
A. 
Every person, firm, association or corporation violating any of the provisions of this chapter is guilty of a misdemeanor and upon conviction there-of shall be punishable by a fine of not more than five hundred dollars, or by imprisonment in the County Jail of Contra Costa County, state of California, for a period of not more than six months, or by both such fine and imprisonment.
B. 
Every person, firm, association or corporation is guilty of a separate offensive for each and every day the provisions of this chapter are violated, and for every day during which any violation of this chapter or its provisions continues, such person, firm, association or corporation shall be punishable therefor as provided in subsection A.
(Ord. 696 § 2, 2002)
The code enforcement officer or duly authorized representative can monitor and enforce as appropriate the provisions of this chapter. No person shall interfere with, oppose or resist any authorized person charged with the enforcement of the chapter while such person is engaged in the performance of her or his duty. Violators may be punished pursuant to Section 1.16.010 of the city of Brentwood's Municipal Code.
(Ord. 696 § 2, 2002; Ord. 1065, 12/12/2023)