Rock Island County, IL Noise Ordinances: Decibel Limits (2026)
Key Facts
- Lowest-band business limit
- 73 dB at 0-75 cycles/sec
- Lowest-band residential limit
- 58 dB at 0-75 cycles/sec
- Highest-band residential limit
- 20 dB over 4,800 cycles/sec
- Measured at
- Nearest residential district boundary
- Penalty
- $25-$200 per offense, § 154.999
Summary
Rock Island County's zoning code sets hard, numeric maximum sound-pressure levels by octave band for the unincorporated county. Section 154.555 caps noise measured at the nearest residential boundary line, with far lower ceilings protecting residential districts than the B-1, B-2, and B-3 business districts, enforced with a calibrated sound level meter.
§ 154.555 NOISE. The following requirements shall apply in all Districts: (A) The sound pressure level, to be measured as described below, shall not exceed the following decibel levels in the designated octave bands when adjacent to the designated types of use districts: Octave Band, Cycles per Second Districts Sound Level in Decibels B-1, B-2, B-3 All Residential 0 to 75 73 58 76 to 150 69 54 151 to 300 65 50 301 to 600 61 46 601 to 1,200 55 40 1,201 to 2,400 48 33 2,400 to 4,800 41 26 Over 4,800 35 20
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2025 S-1: Supplement contains: Local legislation current through Ord. 2024-12-A, passed 12-17-2024; and State legislation current through 2024 Illinois Legislative Service, Pamphlet #6).
Full Breakdown
555(A) runs across eight octave bands, from 0-75 cycles per second up to over 4,800 cycles per second, and sets a separate ceiling for B-1, B-2, and B-3 business districts versus all residential districts. At the lowest band the business limit is 73 decibels against 58 decibels for residential; at the highest band it drops to 35 decibels for business against just 20 decibels for residential, meaning the rule squeezes tighter as pitch rises. 555(B) reaches sounds a meter can't easily capture: objectionable intermittent sounds must still be controlled so they don't become a nuisance to adjacent uses.
555(C)(2). This sits inside the same zoning chapter as the county's vibration standards for B, I-UL, I-1, and I-2 districts, so a single noisy industrial use can trigger both the decibel table and the separate vibration limits depending on what a neighbor experiences at the property line.
Violations & Fines
A § 154.555 violation is punished under § 154.999(A): a forfeiture of $25 to $200 per offense plus prosecution costs, with up to 30 days in the County Jail if the forfeiture and costs go unpaid. Each day the noise source continues to exceed the table counts as a separate, additional offense.
Frequently Asked Questions
Where does the county measure noise from?
Are the decibel limits the same for homes and businesses?
What if a noise is intermittent and hard to capture with a meter?
Sources & Official References
Other rules in Rock Island County
Compare Rock Island County to another location·View the Illinois noise ordinances overview
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