Arroyo Grande Municipal Code Ch. 9.16 Noise

This chapter establishes standards for acceptable exterior and interior noise levels and describes how noise is to be measured. These standards are intended to protect persons from excessive noise levels, which are detrimental to the public health, welfare and safety and contrary to the public interest because they can: interfere with sleep, communication, relaxation and the full enjoyment of one's property; contribute to hearing impairment and a wide range of adverse physiological stress conditions; and adversely affect the value of real property. It is the intent of this chapter to protect persons from excessive levels of noise within or near various residential development and other specified noise-sensitive land uses.

(Prior code § 5-21.01)

As used in this chapter:

"A-weighted sound level" means the sound level in decibels as measured on a sound level meter using the A-weighting network (scale) at slow meter response. The unit of measurement is referred to as "dB."

"Ambient noise level" means the composite of noise from all sources excluding the alleged offensive noise. In this context, the ambient noise level is the normal or existing level of environmental noise at a given location for a specified time of the day or night.

"Decibel, dB" means a unit for measuring the amplitude of a sound, equal to twenty (20) times the logarithm to the base ten (10) of the ratio of the pressure of the sound measured to the reference pressure, which is twenty (20) micropascals.

"Equivalent Sound Level (Leq)" means the sound level containing the same total energy as a time varying signal over a given sample period. Leq is typically computed over one, eight and twenty-four (24) hour sample periods.

"Impulsive sound or noise" means sound of short duration, usually less than one second, with an abrupt onset and rapid decay. Examples of impulsive sound include explosions, hammering and discharge of firearms.

"Intruding noise levels" means the sound level created, caused, maintained or originating from an alleged offensive source, measured in decibels, at a specified location while the alleged offensive source is in operation.

"Noise" means any sound that can be measured on a A-weighted sound level meter.

"Simple tone noise" means any noise which is distinctly audible as a single pitch (frequency) or set of pitches as determined by the city.

"Sound level meter" means any instrument for the measurement of sound levels, which meets or exceeds the American National Standard Institute Standard S1.4-1971 for Type 1 or Type 2 sound level meters, or an instrument and the associated recording and analyzing equipment which will provide equivalent data.

(Prior code § 5-21.02)

The standards of this chapter are not applicable to noise from the following sources:

A. Activities conducted in public parks, public playgrounds and public or private school grounds, including but not limited to school athletic and school entertainment events;

B. The use of any mechanical device, apparatus or equipment related to or connected with emergency activities or emergency work to protect life or property;

C. Safety signals, warning devices, and emergency pressure relief valves;

D. Noise sources associated with construction, provided such activities do not take place before seven a.m. or after ten (10) p.m. or any day except Saturday or Sunday, or before eight a.m. or after five p.m. on Saturday or Sunday;

E. Noise sources associated with the routine maintenance of a residential, commercial, industrial, or public/quasi-public property provided that such maintenance activities take place between the hours of seven a.m. and ten (10) p.m.;

F. Noise sources associated with agricultural land uses, including but not limited to wind machines used for direct climate control, water well pumps and pest-repelling devices, provided that such pest-repelling devices are used in accordance with the accepted standards and practices;

G. Noise sources associated with work performed by the city or private or public utilities in the maintenance or modification of its facilities;

H. Noise sources associated with the collection of waste or garbage from property devoted to other than residential uses;

I. Any activity to the extent regulation thereof has been preempted by state or federal law.

(Ord. 556 § 1F, 2004; Prior code § 5-21.03)

A. The exterior noise level standards of this section are applicable when a land use affected by noise is one of the following noise-sensitive uses:

1. Residential development;

2. Schools, preschools, child care facilities;

3. Hospitals, nursing homes;

4. Churches;

5. Meeting halls, auditoriums, music halls, theaters, libraries, museums;

6. Transient lodging, motels, hotels, bed and breakfast inns, recreational vehicle parks and campgrounds;

7. Playgrounds, parks; and

8. Offices.

B. No person shall create any noise or allow the creation of any noise at any location within the city on property owned, leased, occupied or otherwise controlled by such person which causes the exterior noise level when measured at any of the preceding noise-sensitive land uses to exceed the noise level standards in the following table. When the receiving noise-sensitive land use are playgrounds or parks, the following noise level standards shall be increased by ten (10) dB.

Exterior Noise Level Standards

1 Applies only to uses that operate or are occupied during nighttime hours.

C. In the event the measured ambient noise level exceeds the applicable exterior noise level standard in subsection B of this section, applicable standard shall be adjusted so as to equal the ambient noise level.

D. Each of the exterior noise level standards specified in subsection B of this section, shall be reduced by five dB for simple tone noises, noises consisting primarily of speech or music, or for recurring impulsive noises.

E. If the intruding noise source is continuous and cannot reasonably be discontinued or stopped for a time period whereby the ambient noise level can be measured, the noise level measured while the source is in operation shall be compared directly to the exterior noise level standards.

(Prior code § 5-21.04)

The interior noise level standards of this section are applicable when the land use which is the source of noise and the land use which is affected by noise are both residential uses.

A. No person shall operate or cause to be operated a source of noise within a residential use in any location in the city or allow the creation of any noise which causes the noise level when measured inside a neighboring residential use to exceed the interior noise level standards in the following table:

Interior Noise Level Standards

1 Applies only to uses that operate or are occupied during nighttime hours.

B. In the event the measured ambient noise level exceeds the applicable interior noise level standard in subsection A of this section, the applicable standard shall be adjusted to as to equal the ambient noise level.

C. Each of the interior noise level standards specified in subsection A of this section shall be reduced by five dB for simple tone noises, noises consisting primarily of speech or music, or for recurring impulsive noises.

D. If the intruding noise source is continuous and cannot reasonably be discontinued or stopped for a time period whereby the ambient noise level can be measured, the noise level measured while the source is in operation shall be compared directly to the interior noise level standards.

(Prior code § 5-21.05)

The noise level standards in this section apply to the following noise sources:

A. Air Conditioning and Refrigeration. Notwithstanding the provisions of Section 9.16.040, when the intruding noise source is an air conditioning or refrigeration system or associated equipment installed prior to the effective date of this chapter, the exterior noise level as measured as provided in Section 9.16.070 shall not exceed fifty-five (55) dB, except where such equipment is exempt from the provisions of this chapter. The exterior noise level shall not exceed fifty (50) dB for such equipment installed or in use after one year after the effective date of this chapter.

B. Waste and Garbage Collection Equipment. Notwithstanding the provisions of Section 9.16.040, noise sources associated with the collection of waste or garbage from a residential use by persons authorized to engage in such activity, and who are operating truck-mounted loading or compacting equipment, shall not take place before seven a.m. or after seven p.m., and the noise level created by such activities when measured at a distance of fifty (50) feet in an open area shall not exceed the following standards:

1. Eighty-five (85) dB for equipment in use, purchased or leased within six months from the effective date of this chapter;

2. Eighty (80) dB for the equipment set forth above after five years from the effective date of this chapter;

3. Eighty (80) dB for new equipment purchased or leased after six months from the effective date of this chapter;

4. Seventy-five (75) dB for new equipment purchased or leased after thirty-six (36) months from the effective date of this chapter.

C. Electrical Substations. Notwithstanding the provisions of Section 9.16.040, noise sources associated with the operation of electrical substations shall not exceed an exterior noise level of fifty (50) dB.

(Prior code § 5-21.06)

For the purpose of evaluating conformance with the standards of this chapter, noise levels shall be measured as follows:

A. Use of Meter. Any noise measurement made pursuant to the provisions of this chapter shall be made with a sound level meter using the A-weighted network (scale) at slow meter response. Fast meter response shall be used for impulsive type sounds. Calibration of the measurement equipment utilizing an acoustical calibrator shall be performed immediately prior to recording any noise data.

B. Measuring Exterior Noise Levels. Except as otherwise provided in this chapter, exterior noise levels shall be measured at the property line of the affected noise-sensitive land use listed in Section 9.16.040. Where practical, the microphone shall be positioned three to five feet above the ground and away from reflective surfaces.

C. Measuring Interior Noise Levels. Interior noise levels shall be measured within the affected residential use listed in Section 9.16.050, at points at least four feet from the wall, ceiling or floor nearest the noise source, with windows in the normal seasonal configuration. The reported interior noise level shall be determined by taking the arithmetic average of the readings taken at the various microphone locations.

(Prior code § 5-21.07)

The violations of any of the provisions of this chapter shall be an infraction. The provisions of this chapter may also be enforced by an injunction issued from the Superior Court upon suit of the city. Any violation of the provisions of this chapter shall be deemed to be a public nuisance.

(Prior code § 5-21.08)