Many Amish people have denounced the Discovery Channel’s Amish Mafia TV show, now entering its fourth season, in part because the contrived show has brought them unwanted attention from law enforcement. It furthered a perception they would rather not have out there — that behind the Little House on the Prairie façade lurks a seedy underground rife with drug use, exorcisms, and counterfeit homemade goods.

But the environmental cops have always been much more interested in what was underground in the most literal sense — the pollution seeping into waterways from manure in the soil.

In late 2009, federal agents swooped into a collection of Amish farms in a quiet area of Lancaster County, Pa., where they found troubling evidence of water pollution: High concentrations of nitrates and E. coli bacteria in the water wells, loose manure not properly stored in tanks or sheds, and few livestock fences to keep cows from standing (and presumably defecating) in streams.