A possible solution for one form of water pollution is moving out of the lab and into the field in Nebraska, in a development that could revive some unused wells and save some towns a lot of money.

Animal waste and nitrogen-based agricultural fertilizers contribute to nitrate runoff, which ends up in creeks, streams, rain and, eventually, water systems. Nitrate, that mix of nitrogen and oxygen, can cause serious health problems if it’s too concentrated.

The water we drink is protected by federal rules, which are at the crux of a long-running fight over how far upstream that protection extends.

The Illinois Supreme Court is being asked to settle a fight between two of the state’s environmental regulators. At issue is whether certain waste disposal sites should have to do groundwater testing.