Water Science School

Water Quality

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 particular use based on selected physical, chemical, and biological characteristics

All Water Quality Science Topics

All Water Quality Science Topics

View a list of all of our science topics about water quality.

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Water Quality Data for the Nation

Water Quality Data for the Nation

The USGS National Water Information System (NWIS) contains extensive water-quality data, both real-time and historical, for the nation.

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Filter Total Items: 44
Date published: June 11, 2018
Status: Completed

Hardness of Water

In scientific terms, water hardness is generally the amount of dissolved calcium and magnesium in water. But in layman's terms, you may notice water hardness when your hands still feel slimy after washing with soap and water, or when your drinking glasses at home become less than crystal clear. Learn a lot more about water hardness on the Water Science School site.

Contacts: Ask USGS
Date published: June 9, 2018
Status: Completed

Sediment and Suspended Sediment

Water is nature is never really totally clear, especially in surface water, such as rivers and lakes. Water has color and some extent of dissolved and suspended material, usually dirt particles (suspended sediment). Suspended sediment is an important factor in determining the quality of water.

Contacts: Ask USGS
Date published: June 8, 2018
Status: Completed

Reclaimed Wastewater

Thirsty? How about a refreshing cup of reclaimed wastewater? No, we're kidding. You probably don't drink much reclaimed wastewater (although some people do - see below)! But reclaimed wastewater has many uses, with more promise of usage in the future.

Contacts: Ask USGS
Date published: June 8, 2018
Status: Completed

Urban Water Quality: Sewage Overflows

Wastewater and sewage treatment are important topics in any society, all throughout history and into today. Improperly disposed of or treated sewage can cause disease and harm the ecosystem. That is why when a sewage overflow occurs it garners negative news attention.

Contacts: Ask USGS
Date published: June 8, 2018
Status: Completed

Mining and Water Quality

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.

Contacts: Ask USGS
Date published: June 8, 2018
Status: Completed

Pesticides in Groundwater

Commercial pesticide applicators, farmers, and homeowners apply about 1 billion pounds of pesticides annually to agricultural land, non-crop land, and urban areas throughout the United States. The use of pesticides has helped to make the United States the largest producer of food in the world and has provided other benefits, but has also been accompanied by concerns about their potential...

Contacts: Ask USGS
Date published: June 8, 2018
Status: Completed

Water Quality Sampling Techniques

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.

Contacts: Ask USGS
Date published: June 6, 2018
Status: Completed

Contamination of Groundwater

Groundwater will normally look clear and clean because the ground naturally filters out particulate matter. But did you know that natural and human-induced chemicals can be found in groundwater even if appears to be clean? Below is a list of some contaminants that can occur in groundwater.

Contacts: Ask USGS
Date published: June 6, 2018
Status: Completed

Shocking Fish to Collect Ecologic Data

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.

Contacts: Ask USGS
Date published: June 6, 2018
Status: Completed

Turbidity and Water

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.

Contacts: Ask USGS
Attribution: Water Resources
Date published: June 6, 2018
Status: Completed

Conductivity (Electrical Conductance) and Water

Water and electricity don't mix, right? Well actually, pure water is an excellent insulator and does not conduct electricity. The thing is, you won't find any pure water in nature, so don't mix electricity and water. Our Water Science School page will give you all the details.

Contacts: Ask USGS
Date published: June 6, 2018
Status: Completed

Water Color

Is pure water really clear? Not really—even pure water is not colorless, but has a slight blue tint to it. In the natural world you often see water that is definitely not clear. Sediment and organics color natural water shades of brown or green. And if too much iron in present, even your drinking water can have a brown hue. Read on to investigate water color in the environment.

Contacts: Ask USGS
Attribution: Water Resources