Today’s question: Where does my drinking water come from?

Plain Talk answer: Drinking water comes from two major sources: water that flows aboveground, known as surface water, and water that is pumped from beneath the ground, called groundwater. Surface water comes from lakes, reservoirs and rivers. Groundwater comes from wells that water suppliers drill into aquifers - underground geologic formations of permeable rock. Wells less than 100 feet (30 meters) deep are considered shallow, while deep wells can extend 1,500 to 2,000 feet (450 to 600 meters) below ground.

Springs are another source of freshwater. Springs begin underground as groundwater. When the water is pushed to the surface and flows out of the ground naturally, it becomes a spring. The water then may flow over the surface of the ground as a creek or river, or may form a lake.

The majority of people in the United States - 66 percent - live in areas served by large water systems that rely on surface water. The larger Canadian cities, including Montreal, Toronto, Edmonton and Vancouver, also use surface water.

However, 80 percent of public water systems are in smaller communities that rely on groundwater. About 80 million people in the United States use groundwater supplied through individual wells and municipal groundwater systems. Another 2 million Canadians are supplied by municipal groundwater systems.

If you get your water from a public system, your local water utility explains the specific source of your drinking water in its annual water quality report to customers, and this information often is available on a utility's Web site.

For more information on this and many other water-related topics, check out Plain Talk About Drinking Water by Dr. James M. Symons.