Industrial Noise: Daly City vs South San Francisco
How do industrial noise rules compare between Daly City, CA and South San Francisco, CA?
Daly City and South San Francisco have similar restriction levels.
Daly City, CA
San Mateo County
Daly City Municipal Code § 9.22.010 and § 9.22.030 regulate industrial noise under a qualitative public-nuisance standard rather than fixed decibel limits. Between 10:00 p.m. and 6:00 a.m., no industrial operation may emit noise audible beyond the property line. During daytime hours, industrial noise that disturbs the public peace is prohibited under § 9.22.010 regardless of decibel level.
View full Daly City rules →South San Francisco, CA
San Mateo County
Industrial and commercial noise in unincorporated San Mateo County is controlled through the exterior noise standards of County Code 4.88.330 (measured at nearby residences, schools, hospitals, churches and libraries) and the General Noise Regulation 4.88.350, with construction-noise exemptions limited to set hours under 4.88.360.
View full South San Francisco rules →Key Facts Comparison
| Fact | Daly City | South San Francisco |
|---|---|---|
| Primary ordinance | Daly City MC § 9.22.010 (Disturbing the Peace) | - |
| Nighttime audibility limit | 10 p.m. - 6 a.m., no noise across property line (§ 9.22.030) | - |
| Numeric dB limit | None — qualitative nuisance standard | - |
| Worker-facing standard | Cal/OSHA 8 CCR § 5096 (90 dBA 8-hr PEL) | - |
| Enforcement | Daly City Police + Code Enforcement | Code Enforcement (650) 363-4825 |
| Exterior limits | - | County Code 4.88.330 (Table I) |
| Nuisance standard | - | County Code 4.88.350 |
| Zoning considered | - | Yes - source and impacted area |
| Agricultural mobile sources | - | Exempt 7 a.m.-8 p.m. per 4.88.360 |
Highlighted rows indicate differences between cities.
Daly City FAQ
What's the daytime industrial noise limit in Daly City?
There is no numeric dB(A) limit. § 9.22.010 prohibits any noise that disturbs the public peace, which gives officers and code enforcement broad discretion based on duration, intensity, and complainant accounts.
Can a factory operate at night?
Operations may continue at night, but noise emanating beyond the property line between 10 p.m. and 6 a.m. violates § 9.22.030. Indoor operations with proper soundproofing are typically compliant.
Does Cal/OSHA's noise limit apply to neighbors?
No. 8 CCR § 5096 protects workers inside the facility (90 dBA 8-hr PEL). Community noise exposure is governed by Chapter 9.22.
South San Francisco FAQ
How is industrial noise limited in unincorporated San Mateo County?
By the exterior dBA limits in 4.88.330 measured at nearby residences and similar properties, plus the general nuisance rule in 4.88.350. Zoning of the source and the affected area is one factor the County weighs.
Are agricultural operations exempt?
Section 4.88.360 exempts certain agricultural noise, including frost-protection equipment, and limits exempt mobile agricultural sources to roughly 7:00 a.m. to 8:00 p.m.
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