Decibel Limits: Chino vs Ontario
How do decibel limits rules compare between Chino, CA and Ontario, CA?
Chino and Ontario have similar restriction levels.
Chino, CA
San Bernardino County
Chino Municipal Code §9.40.040 (Exterior Noise Standards) establishes maximum permitted noise levels at the receiving (residential) property line: 65 dBA during daytime hours (7 a.m. to 10 p.m.) and 55 dBA during nighttime hours (10 p.m. to 7 a.m.). Measurement is per §9.40.020: A-weighted scale, slow response, referenced to 20 micropascals, using a sound level meter that meets ANSI specifications. Noise sources in commercial and industrial zones must comply with the residential standard when measured at the nearest residential property line. The standard is exceeded when the level is exceeded for any 30 minutes in an hour; lower thresholds (typically 5 dBA below the base) apply for shorter cumulative durations (15 min, 5 min, 1 min, instantaneous).
View full Chino rules →Ontario, CA
San Bernardino County
Ontario applies exterior decibel standards set in zoning and noise rules. Residential limits are about 55 dBA daytime and 50 dBA nighttime at the property line, with higher limits in commercial and industrial zones.
View full Ontario rules →Key Facts Comparison
| Fact | Chino | Ontario |
|---|---|---|
| Daytime exterior limit (residential) | 65 dBA, 7 a.m.–10 p.m. | - |
| Nighttime exterior limit (residential) | 55 dBA, 10 p.m.–7 a.m. | - |
| Measurement standard | CMC §9.40.020 — A-weighted, slow response, 20 µPa reference | - |
| Duration trigger | Standard violated if exceeded any 30 minutes in any hour | - |
| Pure-tone penalty | +5 dBA added to measured level | - |
| Key exemptions | Emergency, schools, permitted events, aircraft, agricultural ops | - |
| Daytime Residential | - | about 55 dBA |
| Nighttime Residential | - | about 50 dBA |
| Measurement | - | At receiving property line |
| Adjustments | - | Impulsive or tonal reductions |
| Enforcement | - | Code Enforcement meter readings |
Highlighted rows indicate differences between cities.
Chino FAQ
How is the 65 dBA limit measured — at my house or at the source?
Per CMC §9.40.020, measurement occurs on the receiving property (the complainant's property line or at a point of human use) using an ANSI Type 2 (or Type 1) sound level meter set to A-weighting, slow response. The reading is taken at least 4 feet above ground and away from reflecting surfaces.
What's a 'pure-tone' penalty?
If the offending noise contains a distinct audible tone (e.g., a whine, hum, or beep) or is cyclically varying or impulsive (banging), CMC §9.40 adds 5 dBA to the measured level before comparing to the limit. So a 60 dBA pure-tone hum is treated as 65 dBA — exactly at the daytime limit and over the nighttime limit.
Ontario FAQ
What is the legal noise level in Ontario residential zones?
Typically about 55 dBA during the day and 50 dBA at night measured at the receiving property line, with stricter limits for impulsive or tonal sound.
How does the city prove a decibel violation?
Code Enforcement uses a calibrated meter at the property line, averages readings, and considers any tonal or impulsive adjustments before issuing a citation.
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