Linn County, IA Noise Ordinances: Decibel Limits (2026)
Key Facts
- Residential noise cap
- 55 dBA / 65 dBC daytime
- Non-residential cap
- 65 dBA / 75 dBC
- Testing hours
- 8 a.m.-6 p.m., weekdays only
- Noise study required
- Every 5 years, by certified engineer
Summary
Large gas-fired power plants and nuclear facilities in unincorporated Linn County can't exceed 55 dBA near homes (65 dBA elsewhere), and routine noisy maintenance is limited to weekday daytime hours under the county's EU-2 zoning standards.
(7)Noise Analysis for gas-fired electric generating facility. No operating ...facility shall produce decibel levels exceeding any of the following limitations...: a.The average hourly noise level shall not exceed (55) dBA or (65) dBC as measured from the outer wall of any occupied structure within residentially zoned property adjacent to the proposed development. ...b.Routine ...testing, maintenance, and construction activities...shall be limited to the hours of 8:00 a.m. to 6:00 p.m., Monday through Friday, unless otherwise approved by the zoning administrator.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 16).
Full Breakdown
Linn County created an EU-2 Exclusive Use district for gas-fired electric generating facilities and nuclear energy plants, and it carries a numeric noise cap: the average hourly noise level can't exceed 55 dBA or 65 dBC measured from an occupied structure on adjacent residential land, or 65 dBA/75 dBC where neighbors aren't residential. Routine testing, maintenance, and construction noise is limited to 8:00 a.m.-6:00 p.m., Monday through Friday, unless the zoning administrator approves otherwise. A certified acoustics professional must run a pre- and post-construction noise study, plus a follow-up every five years. Neighboring owners can waive the limit in writing. A nearly identical decibel standard applies to the county's large-scale data center district.
Violations & Fines
Exceeding the decibel or testing-hour limits is a UDC violation, enforced as a county infraction with civil citation and fines, injunctive abatement, or prosecution as a simple misdemeanor under Ch. 1, Art. II.
Frequently Asked Questions
Does this noise limit apply to ordinary factories in Linn County?
Can neighbors agree to a louder limit?
Sources & Official References
Other rules in Linn County
Compare Linn County to another location·View the Iowa noise ordinances overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.