Water quality

Water quality is a measurement of how suitable water is for a particular use, like drinking or irrigation. Drinking water quality standards are based on the health effects that are likely to occur if a person is exposed to poor water. Industrial or agricultural water supplies will require different water standards. Water contaminants can be natural or man-made. Contaminants can include bacteria, metals, and man-made chemicals like pesticides or pharmaceutical drugs. Other natural properties of water can affect its quality, such as pH and dissolved minerals (such as salts or calcium). Contamination can also alter these natural properties.

Why does water quality matter?

Survey of water quality in a mine water filtration pond. Credit: Photo by Ron Nichols, courtesy of USDA NRCS

Contaminants are harmful to human health, especially to vulnerable populations such as the elderly or the very young. The quality of a stream or wetland affects everyone's health, from the plants and animals that live in it to the people who live downstream. If water is unsuitable for a particular purpose, we have to find alternative resources, sometimes at high cost.

How does geoscience help inform decisions on water quality?

A woman pours herself a glass of water. Credit: EPA

Hydrologists, environmental engineers, and geologists monitor the quality of surface water and ground water for society's needs, especially for human consumption. They find the origin of natural and man-made contaminants, and determine ways to remove them.

Introductory resources

• A Primer on Water Quality, U.S. Geological Survey

A basic overview of water quality, how it is measured, and how natural and human processes affect it.​

See also

• Water Quality Basics, American Geosciences Institute
• Climate
• Drought
• Floods
• Water availability
• Weather hazards

External links

find literature about Water quality