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 6, 2018
Status: Completed

Pharmaceuticals in Water

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.

Contacts: Ask USGS
Attribution: Water Resources
Date published: June 5, 2018
Status: Completed

Dissolved Oxygen and Water

Dissolved oxygen (DO) is a measure of how much oxygen is dissolved in the water - the amount of oxygen available to living aquatic organisms. The amount of dissolved oxygen in a stream or lake can tell us a lot about its water quality.

Contacts: Ask USGS
Date published: June 5, 2018
Status: Completed

Biological Oxygen Demand (BOD) and Water

You don't often think that water bodies contain oxygen, but water does contain a small amount of dissolved oxygen. A small amount, but it is essential for life in the water. Biological oxygen demand (BOD) generally represents how much oxygen is needed to break down organic matter in water.

Contacts: Ask USGS
Attribution: Water Resources
Date published: June 5, 2018
Status: Completed

Environmental DNA (eDNA)

Environmental DNA (eDNA) is organismal DNA that can be found in the environment. Environmental DNA originates from cellular material shed by organisms (via skin, excrement, etc.) into aquatic or terrestrial environments that can be sampled and monitored using new molecular methods. Such methodology is important for the early detection of invasive species as well as the detection of rare and...

Attribution: Water Resources
Date published: June 5, 2018
Status: Completed

Bacteria and E. Coli in Water

Water, like everything else on Earth, including you, is full of bacteria. Some bacteria are beneficial and some are not. Escherichia coli (E. coli) bacteria, found in the digestive tract of animals, can get into the environment, and if contacted by people, can cause health problems and sickness. Find out the details here.

Contacts: Ask USGS
Attribution: Water Resources
Date published: June 5, 2018
Status: Completed

Impervious Surfaces and Flooding

The banner picture shows it all — Superhighways! Streets and pavement! Driveways! House roofs! These are all "impervious surfaces"; impervious to the water from precipitation. When it rains in this locale, water no longer seeps into the ground, but now runs off into storm sewers and then quickly into local creeks. Localized flooding is too often the result.

Contacts: Ask USGS
Date published: June 5, 2018
Status: Completed

Phosphorus and Water

Nutrients, such as nitrogen and phosphorus, are essential for plant and animal growth and nourishment, but the overabundance of certain nutrients in water can cause a number of adverse health and ecological effects.

Contacts: Ask USGS
Date published: May 21, 2018
Status: Completed

Nitrogen and Water

Nutrients, such as nitrogen and phosphorus, are essential for plant and animal growth and nourishment, but the overabundance of certain nutrients in water can cause several adverse health and ecological effects.

Contacts: Ask USGS