Draft noise rules target emergency generators and allow recurring test permits

Staff proposed revisions to Marshalltown's noise control ordinance to better capture low‑frequency generator noise and to create a permit pathway for recurring generator tests related to large facilities. Staff said the draft adds C‑weighted sound metrics (low frequency) to the existing A‑weighted limits and clarifies that sound measurements should be taken at the receiving property — the place where residents hear the noise.

The draft also creates a recurring generator‑test permit reviewed and enforced by the police department and tightens exemptions so that only actual emergency outages qualify for temporary unrestricted operation. Staff proposed an escalation framework for prolonged outages: automatic operation for the first 0–7 days, notification and oversight for outages 7–30 days, and a substantive review if operations exceed 30 days.