Linn County, IA Data Centers & Crypto Mining: Data Center Noise Limits (2026)

(l)Noise analysis. No operating data center equipment shall produce decibel levels exceeding any of the following limitations, with the exception of initial construction and routine maintenance. Adequate setbacks and effective sound mitigating equipment shall be used to comply with these limitations: (1)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. For property adjacent to the proposed development that is not residentially zoned, the average hourly noise level shall not exceed 65 dBA or 75 dBC as measured from the outer wall of any occupied structure. The average decibel limit is specific to source of the sound and does not count against cumulative ambient decibel levels as established in a baseline acoustic evaluation. (2)Equipment testing, maintenance activities, and construction activities that generate elevated noise, including generator testing, 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. County approval for excessive noise generation shall not be unreasonably withheld. (3)The average hourly decibel level may be exceeded during short-term events such as severe windstorms.