Industrial Noise: San Mateo vs South San Francisco
How do industrial noise rules compare between San Mateo, CA and South San Francisco, CA?
San Mateo and South San Francisco have similar restriction levels.
San Mateo, CA
San Mateo County
Industrial and commercial noise in San Mateo is regulated by the noise ordinance Chapter 7.30, which sets maximum permissible sound levels by noise zone. Noise Zone 3 (commercial) allows 60 dB at night and 65 dB during the day. Zone 4 (industrial) allows 70 dB at all times.
View full San Mateo 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 | San Mateo | South San Francisco |
|---|---|---|
| Zone 3 Night | 60 dB (10 PM–7 AM) | - |
| Zone 3 Day | 65 dB (7 AM–10 PM) | - |
| Zone 4 | 70 dB (all times) | - |
| Measurement | At property line | - |
| Code Reference | SMMC §7.30.040 | - |
| 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 |
| Enforcement | - | Code Enforcement (650) 363-4825 |
Highlighted rows indicate differences between cities.
San Mateo FAQ
What are the noise limits for businesses in San Mateo?
Commercial Zone 3: 60 dB night / 65 dB day. Industrial Zone 4: 70 dB at all times. Measured at the property line.
What about short-duration loud noises?
Higher levels are permitted for shorter durations: +5 dB for 15 minutes, +10 dB for 5 minutes, +15 dB for 1 minute, +20 dB for any period.
How do I report commercial noise?
Contact Code Enforcement at 650-522-7200 or the San Mateo Police Department non-emergency line at 650-522-7700.
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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