Every day, U.S. agriculture guzzles 117 billion gallons of freshwater (the single largest demand after the power industry). And ag creates water pollution issues from coast to coast. Here are a few examples. Click different water sources on the map.

Hangman Creek Around Hangman (aka Latah) Creek in Washington state, wheat grows well in the light, silty soil and livestock range freely. The downside is topsoil erosion—in spring, the raging creek looks like chocolate milk—and high coliform counts. The local Coeur d’Alene tribe is working to restore this once-legendary fishing stream. Water-quality experts are advo­cating a no-till growing method to lessen soil disruption and are encouraging efforts to keep cattle out of the creek.

Sacramento River California relies on irrigation to grow vegetables, fruits and nuts. Water use here is a delicate balance. In the San Joaquin River Delta, for example, levees manage saltwater, rice paddies and fresh­water for irrigation. Residues from pesticides applied to almond and fruit orchards pollute the Feather and Sacra­mento rivers that empty into the Delta. Targets for reduced usage of certain pesticides have been met, but the EPA is now finding pollution from new insecticides.

Colorado River When the 1,450-mile Colorado River reaches the Gulf of California there’s barely any water left. Three-quarters of the river’s water goes to irrigate around 5.5 million acres of cropland in six states, nearly half of that outside the river basin in places like California’s Imperial Valley. “If you’re eating carrots or lettuce in the winter, chances are the Colorado irrigated those crops,” says Aaron Derwingson, agriculture coordinator for the Nature Conservancy’s Colorado River Project.

Big Blue River Nebraska has nearly 10 million acres planted in corn. Atrazine and glyphosate (Roundup), herbicides used to control weeds in corn, have been found in wells and water supplies here. The World Health Organization has deemed glyphosate a probable human carcinogen. In 2016 the EPA released a draft assessment of atrazine that cited excessive risk for animals and fish. These chemicals may linger in water and in aquatic organisms including fish.

Raccoon River Iowa is our top pork-­producing state. To make its fine, poorly drained soils suitable for corn and soy (much of it grown to feed pigs), Iowa farmers have built underground tiled drainage systems. The tiles quickly drain water, along with nutrients from fertilizer. One result: the Raccoon and Des Moines rivers, which provide drinking water for Des Moines, have nitrate levels among the highest in the U.S. A federal judge recently dismissed a suit by the Des Moines Water Works that aimed to stanch the pollution.

Cache River Expansive plantings of rice, soy and cotton have shrunk the forest that once dominated the Cache River basin in northeast Arkansas. Pollutants from farming, including lead and eroded soil, contribute to the dead zone downstream in the Gulf of Mexico. Some positive news: the 67,500-acre Cache River National Wildlife Refuge—where the presumed-extinct ivory-billed woodpecker was spotted in 2005—is in the process of expanding.

Gulf of Mexico The dead zone that forms each summer in the Gulf is one of the largest globally. Polluted water from the Mississippi River sits on top of the saltwater and prevents oxygen-rich surface water from mixing with the deep waters. Starved of oxygen, the Gulf’s native fish and wildlife must leave or die. The nitrogen and phosphorus in the Mississippi River come largely from agricultural sources. About one-third of the 1.2 million square miles that drain via the Mississippi to the Gulf are cultivated cropland.

Western Lake Erie Basin Runoff from soy and corn production (mostly for animal feed) around the Maumee and other rivers in the Western Lake Erie Basin around Toledo, Ohio, has led to elevated phosphorus, algae blooms and a dead zone in Lake Erie. An increase of soybean crops grown using no-till agriculture has been good for erosion control. But some experts think no-till may contribute to the problem by leaving phosphorus fertilizers in the soil’s top layers where they are more susceptible to being washed off by storms.

Catskill / Delaware Watershed New York City, home to 8.5 million people, is renowned for the quality of its drinking water, thanks to careful oversight of the watershed that surrounds its reservoirs in the Catskills. Over the past 20 years NYC has committed $1.7 billion to a comprehensive watershed-protection program that aims to protect drinking water at its source, including by acquiring land to preserve open space. The city has also worked with hundreds of watershed farmers to create whole-farm plans, build new farm infrastructure and improve the quality of runoff from farmlands into nearby streams. NYC’s programs are considered an international model for source-­water protection.

Lake Champlain Lake Champlain, which borders Vermont, New York and Canada, sees toxic algae blooms each summer. These algae blooms are fed by excess phosphorus in the lake, the largest source of which comes from farms. Vermont has passed legislation mandating improved farming methods to reduce agricultural pollution, though it may take years for it to pay off.

Chesapeake Bay Large and small farms alike pollute the Chesapeake Bay. Nitrogen and phosphorus runoff from large chicken farms on Maryland’s Eastern Shore has lessened due to environmental regulation, but nutrients lingering in the soil continue to leach into rivers. Small-scale traditional family farms in southeastern Pennsylvania contribute to the pollution as well—these low-tech operations often lack systems for manure storage or keeping livestock out of streams.

Cape Fear River North Carolina became the nation’s second-­largest pork producer after the state loosened environmental regulations starting in the ’80s. Now hogs in concentrated animal feeding operations (CAFOs) surround the Cape Fear River, which flows into the Atlantic. Animal waste—collected in lagoons and sprayed on fields—pollutes ground­water and surface water with nitrogen, phosphorus, heavy metals (added to feed for animal nutrition) and fecal bacteria including E. coli.