DES MOINES, Iowa (AP) — Iowa officials have signed an agreement with the U.S. Environmental Protection Agency that increases the number of livestock farms routinely inspected, requires more farms to obtain permits, and more strictly enforces violations when manure leaks into rivers.

The Iowa Department of Natural Resources signed the work plan Wednesday after years of negotiating with EPA, which had threatened to take over enforcement of federal Clean Water Act rules itself if Iowa didn’t step up.

The agreement requires on-site inspections of farms with more than 1,000 cows or 2,500 hogs. That’s about 3,200 farms in Iowa. Smaller farms also may be inspected if they’ve had recent spills or are near streams or rivers. Environmental groups which have lobbied for stricter enforcement say the plan is a good first step.