Surface-Water Quality

The U.S. Geological Survey (USGS) offers you the most comprehensive information about the natural water cycle anywhere, and, our information is available in many languages. Here you can download our water cycle diagrams as well as other educational products to assist you in the classroom or on your own learning adventure!

What is in that water that you just drank? Is it just hydrogen and oxygen atoms? Is it safe for drinking? All water is of a certain "quality" (and you can't tell by just looking), but what does "water quality" really mean? It can be thought of as a measure of the suitability of water for a particular use based on selected physical, chemical, and biological characteristics. Here at the Water...

Learn what happens at a wastewater treatment plant.

Learn about water quality using pictures

What is in that water that you just drank? Is it just hydrogen and oxygen atoms? Is it safe for drinking? All water is of a certain "quality" (and you can't tell by just looking), but what does "water quality" really mean? Water full of dirt and grime might work fine for a tomato plant but would you want to drink it? Water quality can be thought of as a measure of the suitability of water for a...

Wastewater is used water. It includes substances such as human waste, food scraps, oils, soaps and chemicals. In homes, this includes water from sinks, showers, bathtubs, toilets, washing machines and dishwashers. Businesses and industries also contribute their share of used water that must be cleaned.

There's no end to the effects that urbanization can have on water bodies. Millions of people; landscape manipulation; waste material; dumping of chemicals and fertilizers; withdrawing water for peoples' uses. As you expect, urbanization rarely improves water quality, but in order to prevent problems, one needs to understand how urbanization affects the local waters.

Mine drainage is metal-rich water formed from a chemical reaction between water and rocks containing sulfur-bearing minerals. Problems that can be associated with mine drainage include contaminated drinking water, disrupted growth and reproduction of aquatic plants and animals, and the corroding effects of the acid on parts of infrastructures such as bridges.

Checking the water quality of the Nation's streams, rivers, and lakes is one of the main responsibilities of the U.S. Geological Survey (USGS). Physical water measurements and streamflow are almost always taken, but often water samples are needed for chemical analyses, and sampling must follow strict guidelines to collect scientifically-viable samples.

Collecting samples of water isn't the only way to test water quality. The USGS actually collects fish to see if and how they were affected by local pollution and chemicals in the water, such as pesticides. Read on to find out more.

Lucky for us all, our drinking water is almost always clear (very low turbidity). Other water, such as the creek behind your house after a rainstorm, is likely to be highly turbid—brown with floating sediment. Turbidity is the clarity of water and it is an important factor in water quality.

There is a growing concern about the occurance of pharmaceuticals in water bodies and in drinking water. Pharmaceuticals get into the water supply via human excretion and by drugs being flushed down the toilet. You might think wastewater treatment plants would take care of the situation, but pharmaceuticals pass through water treatment.