Nonpoint Source Pollution

Nonpoint source pollution is the nation's biggest water quality problem and occurs when water runs over the ground - due to rainfall, snowmelt, or irrigation - and picks up pollutants along the way, carrying them to lakes, rivers, and coastal waters. These pollutants include fertilizer, grease, and oil.


"Water is Life," as the saying goes. Like all life, we are mostly composed of it – and must replenish it on a regular basis to stay alive. Until now, this hasn't been a problem – at least for those of us who don't live in deserts – because water has always been comparatively plentiful. We took it for granted, even polluting the rivers, streams, and wetlands that provide to us, because there was still enough to go around. But the advent of climate change and its expected impacts on large portions of the country, together with the accumulated impact of pollution, means that we need to start taking better care of the resources that provide us with our freshwater.

Wetlands act as both natural filtration systems and buffers against flooding but, reduced by drainage for development and saturated with agricultural runoff, insecticides from lawn use, and bacteria from faulty septic systems, their functions are failing. What can you do? Use non-toxic products for household cleaning and lawn care; keep lawns and driveways free of pet waste, fertilizers and motor oil; and contact your local state agencies and environmental organizations to check out the volunteer opportunities for protecting wetlands, rivers, and streams.

Turtle swimming among coral

US Coral Reefs in a Warming Ocean

As the oceans around the US become warmer & more acidic due to greenhouse gas emissions, the health & survival of coral reef ecosystems are threatened
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Aerial view of rocks and beach

Stirring up the Seven Seas

By riding the global ocean conveyor belt, seawater may have traveled the planet—and the seven seas—supporting the global food chain on its way.
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Irrigating fields

Future Increases in Water Demand

In many areas of the United States, the demand for freshwater is likely to increase while supplies decrease due, in part, to a changing climate.
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Waterway estuary

Groundwater and the Rising Seas

Changes in precipitation and rising sea levels may reduce the availability of freshwater for coastal communities by saltwater infiltration.
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Bridge on the Delaware River

A River Ran Through It

Climate change impacts the quality and quantity of water in US rivers. Observed and projected changes variably affect regional water resources.
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Sea urchin shells

Marine Life and Ocean Acidity

Increasing ocean acidity decreases the ability of shells and other calcium carbonate structures, such as coral skeletons, to form.
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Sandbags on eroding east coast

Sea Level Rise

Global sea levels are rising at an accelerating rate, and climate change is likely to speed up the rate of sea level rise over the next century.
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View of an iceburg

Diminishing Arctic Sea Ice

Land and sea ice cover in the Arctic have decreased since the late 1970s and the trend is expected to increase in the future due to a warming climate.
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Snowpack on mountains

Snowpack, Hydropower, and Water Supply

This water source is even more useful in the spring and summer when it melts and releases water to sustain ecosystems and water supplies.
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Infographic of Fix a Leak Week, with text and imagery saying "check" next to a toilet, "fix" next to a wrench and pipes, and "replace" next to a showerhead

Be a Leak Detective

The average American family can waste more than 10,000 gallons of water from easy-to-fix household leaks. That’s about 270 loads of laundry!
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Infographic: Wetlands Work for Us

Wetlands Work for Us

Wetlands support diverse fish & wildlife species, filter pollutants from rain water runoff, recharge groundwater supplies, and prevent flooding.
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Wasting water in a drought, dripping faucet

Save Water During a Drought

If your area is experiencing a drought, you can help your community by reducing water use at home.
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Bathroom accessories

Household Water Use

Each day in the US, about 27.4 billion gallons of water are withdrawn and delivered from surface water and groundwater sources for residential use.
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Water Quality

Do Your Part to Protect Water Quality

Give these tips a try to protect water quality where you live.
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