Runoff from agriculture is the biggest polluter of the country's river and stream water, according to the U.S. Environmental Protection Agency (EPA), and it has been fingered for hypoxic dead zones and toxic red tide algae blooms.

But how much of that runoff makes it into people's drinking water closer to home? In agricultural areas, it can be enough to cause persistent health problems, including diarrhea and other infections, according to a report today in The New York Times.

"Sometimes it smells like a barn coming out of the faucet," Lisa Barnard, a Wisconsin resident told the Times. Barnard's well water tested positive for various contaminants and bacteria, including E. coli—which point not just to any runoff, but that coming from excess manure, according to the Times piece.

Beef and dairy farms often dispose of manure and other waste by shipping it out as fertilizer for crops, but "there just isn't enough land to absorb that much manure," said Bill Hafs, a Wisconsin county official who is angling for more stringent rules and enforcement, in an interview with the Times. When heavy rains or early spring melts come, excess waste can find its way into rivers and streams and also into groundwater—and into wells.

Brown County, where Hafs works, has about a quarter of a million people, according to the U.S. Census Bureau, and about 41,000 dairy cows, which is about six people per cow. And as Hafs noted, "one cow produces as much waste as 18 people."  And that is plenty of poo, according to many residents whose wells have been contaminated.

"More than 30 percent of the wells in one town alone violated basic health standards," Hafs told the Times. "It's obvious we've got a problem." But he and others who have raised a stink about the contamination have been met with powerful agricultural lobbies. "We don't have the laws to force people to stop" dumping it, Hafs added. Dairy farms in Brown County create about a million gallons of waste a day, the Times reports. 

For the most part, biological contaminants from farms that runoff into rivers or filter down into groundwater are regulated only by local laws. The Clean Water Act's jurisdiction is constrained largely to pollutants in water that is moving through manmade water supplies, such as aqueducts or pipes. The EPA does regulate farms that have more than 700 cows, but enforcement has been lax, the newspaper noted.

"The challenge now is for EPA and Congress to develop solutions that represent the next step in protecting our nation's waters and people's health," Lisa Jackson, the EPA administrator, said in an interview with the Times.

Image courtesy of canadianfamily via Flickr