Sources of Pure Water

• Water covers three-quarters of the earth's surface. Of that supply, 97 percent of the Earth's water is saline and three percent is fresh. According to the Environmental Protection Agency (EPA), the Safe Drinking Water Act guarantees the United States has one of the cleanest supplies of drinking water in the world. According to Environment Canada, 99 percent of the world's sources of pure water are found in icecaps and glaciers, ice fields or underground.

Icecaps and Glaciers

• Packed snow at high elevation becomes glacial ice. glacier image by Philippe Minisini from Fotolia.com

  Sources of pure water are frozen in polar ice caps and in high mountain glaciers. Packed snow at high elevation becomes glacial ice. Gravity pulls the snow downslope like a frozen river. The snow melts at lower elevations and becomes a stream flow.

  According to the United States Geological Service (USGS), three percent of the earth's water is fresh. 69 percent of fresh water is locked in icecaps and glaciers. 10 percent of the earth is covered with glaciers, mostly found in Greenland and Antarctica, which contains 70 percent of the world's pure water.

  North America's longest glacier is the Bering Glacier in Alaska, which measures 127 miles long. Glaciers provide 470 billion gallons of fresh water each summer to Washington state alone.

Ground Water

• Ground water is an essential and vital source of pure water. haweswater from the rigg image by Kevin Eaves from Fotolia.com

  Ground water is an essential and vital source of pure water used for drinking and washing. It can be found almost everywhere underground. According to the USGS, roughly 31 percent of the earth's pure water comes from underground.

  There is a hundred times more water in the ground than there is in rivers and lakes. Rain falls and seeps underground into aquifers. Aquifers filter the water with sand, clay and rock formations.

  Groundwater occurs close to the earth's surface. According to the USGS, groundwater travels slowly underground at a downward angle and eventually seeps into streams, lakes and oceans. Many communities drill wells through the soil and rock into aquifers to reach the supply of fresh water.

Ice Fields

• Ice fields are a vital source of fresh water for North America. davidson glacier image by rich fater from Fotolia.com

  Ice fields are a vital source of fresh water for North America. Ice fields are large masses of ice, formed on land by compacted and recrystallized snow. They connect glaciers or ice streams.

  Ice fields move very slowly down slopes due to their extreme weight. The runoff is crucial for millions of people, agriculture, industry, hydroelectric development and drinking water.