A growing number of Iowa communities — of all sizes and from every corner of the state — are working with local farmers to improve the quality of their drinking water sources.

That collaboration, according to municipal and state regulatory officials, is helping communities meet federal standards for nitrogen, phosphorus and other nutrients, hold down costs and build stronger and lasting relationships with farmers in their areas.

“Most of our communities have always had a very good relationship with their local farmers, and they want to build on that,” said Dustin Miller, general counsel for the Iowa League of Cities. “These collaborations are helping communities offset the cost of building expensive water treatment plants and creating a win-win situation.”

To reduce nutrient loss and help their communities, farmers are stepping up to rework their traditional cropping patterns to add cover crops and are adding ...