Chino, CA Noise Ordinances: Decibel Limits (2026)

Section 9.40.030 assigns every parcel in the city to one of three noise zones: Zone I is all single-, double- and multiple-family residential property; Zone II is all commercial property; and Zone III is all manufacturing or industrial property. Section 9.40.040 then sets the numeric exterior standards that apply at the boundary of Zone I residential property, explaining that "higher noise levels are permitted during the day (seven a.m. to ten p.m.) than the night (ten p.m. to seven a.m.)." The table sets five tiers by cumulative duration: a sound level (L50) of 55 dBA daytime / 50 dBA nighttime may not be exceeded for more than 30 minutes in any hour; 60/55 dBA (L25) for more than 15 minutes; 65/60 dBA (L8.3) for more than 5 minutes; 70/65 dBA (L1.7) for more than 1 minute; and a hard ceiling of 75 dBA daytime / 70 dBA nighttime (Lmax) that may not be exceeded for any period at all.

Each of those limits is reduced by 5 dBA for impulse noise, simple-tone noise, or noise consisting of speech or music, unless the ambient noise level already exceeds the resulting standard, in which case ambient becomes the new floor. A parallel interior standard applies inside a neighboring dwelling under § 9.40.050. Chapter 9.40 exempts permitted public events, school athletics, emergency alarms limited to thirty minutes of sounding, agricultural equipment operated outside 8:00 p.m.-7:00 a.m. on weekdays (or anytime Sunday/federal holidays), and property-maintenance activity between 7:00 a.m. and 8:00 p.m. weekdays or 9:00 a.m. to 8:00 p.m.

Sunday, per § 9.40.060. Construction noise gets its own carve-out at § 9.40.060(D): a 65 dBA standard plus the Table B allowance applies, but only during the hours set by the city's construction-hours ordinance, § 15.44.030. Exceeding the § 9.40.040 or § 9.40.050 standards is itself declared "prima facie evidence of a violation" under § 9.40.160, shifting the practical burden onto the noise source's operator once a measurement is taken.