Industrial Noise: Daly City vs San Mateo
How do industrial noise rules compare between Daly City, CA and San Mateo, CA?
Daly City and San Mateo 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 →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 →Key Facts Comparison
| Fact | Daly City | San Mateo |
|---|---|---|
| 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 | - |
| 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 |
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.
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.
Compare other topics
See how Daly City and San Mateo compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool