IDEQ tells Middleton to renew MS4 stormwater permit or face enforcement risk; agency warns of third-party suits and fines

Idaho Department of Environmental Quality compliance staff told the council the city must apply to renew its MS4 (municipal separate storm sewer system) permit and explained the potential consequences if coverage lapses.

"You're in a little bit of a different situation...you were part of that Nampa urbanized area...you were issued a permit. That was a requirement at that time," IDEQ compliance officer Heidi Kaye said. She told council the permit contains a provision that prevents cities that once had MS4 coverage as part of an urbanized area from dropping out simply because later census boundaries change.

Kaye said staff expected the city—s renewal application by April 3 and that the current permit expires Sept. 30; she warned that failure to maintain coverage would expose the city to DEQ enforcement and to third-party lawsuits. "Those third party lawsuits...have the ability to propose a fine of up to $64,000 per day per violation," Kaye said, urging timely application and noting the state—s permitting backlog could delay issuance if coverage lapsed.

IDEQ and city staff discussed potential options to streamline compliance and to identify the minimum requirements that would keep the city in compliance without unnecessary extra expense. Council requested further legal follow-up and an executive-session briefing on potential liabilities and next steps.

No council decision to change the city—s permit status was made at the meeting; staff and IDEQ committed to continued coordination to prepare the renewal application and explore cost-control measures.