Q. In towns and cities what is the main cause of pollution of drinking water sources?

A. The major source of pollution in towns and cities is rainwater that flows into street catch basins (called urban runoff or stormwater runoff). While the rainwater alone is not necessarily harmful, it frequently carries untreated waste products from our streets and yards directly to rivers, lakes, and streams- our drinking water sources.

Q. Why does drinking water often look cloudy when first taken from a faucet and then clear up?

A. The cloudy water is caused by tiny air bubbles in the water similar to the gas bubbles in carbonated soft drinks. After a while, the bubbles rise to the top and are gone. This type of cloudiness occurs more often in the winter, when the drinking water is cold.

Q. Why is some drinking water stored in large tanks high above the ground?

A. Two reasons. First, this type of water storage ensures that water pressure and water volume are sufficient enough to fight fires, even if the electricity that normally pumps water is turned off. The second reason is to provide an extra source of drinking water during the day when water use is high. The water storage tanks are refilled at night when drinking water use is low.

These questions and answer above are from Plain Talk about Drinking Water: Questions and Answers About the Water You Drink by Dr. James M. Symons, published by American Water Works Association, copyright 1997

Q. Why does chilled tap water taste better than water straight from the tap?

A. Water that is refrigerated overnight in a sealed container does taste better as it has been given time to settle. We recommend keeping a jug of water at all times in the refrigerator. This also gives you the benefit of always having a cool drink of water.

Q. Do we have hard water?

A. Hard water is defined by the amount of calcium and magnesium present in the water. Hard water has a relatively high level as compared to soft water which has a low level. Austin tap water is considered moderately hard. Hardness testing conducted throughout 2011 showed we have an average hardness of 98 milligrams per liter or about 5.7 grains per gallons.

Q. Is fluoride added to Austin's water?

A. Fluoride, which is a substance added to reduce cavities, is added to our water. The Center for Disease Control recommends a concentration of 0.7 mg/l, and our average levels in 2011 were 0.65 mg/l. See section on fluoride in this web site.

Q. Is my water safer with water purification devices?

A. Water from the Austin water supply is safe to drink. We recognize that it is your personal choice to purchase water purification devices, they have been known to cause problems in the quality of drinking water due to the lack of proper filter replacement. These devices are not tested or regulated by the state or federal government.

Q. Is chlorine a safe disinfectant for drinking water?

A. Austin uses chloramine to disinfect our drinking water. Chloramine is used in municipal water treatment and is the most effective way to ensure that water stays disinfected as it travels through water delivery systems. Chlorine prevents water-borne epidemics such as cholera, typhoid, and hepatitis.

Q. How does Austin water rate?

A. Our water meets and exceeds all federal, state and local standards and has received the highest possible "Superior" rating by the Texas Commission on Environmental Quality. To review our annual water quality against the USEPA drinking water standards, please go to our web site on "Water Quality", as shown on home page of this site.

Q. Why does dishwater or the dishwasher leave spots on glasses?

A. The spots that may appear on glassware after washing and air-drying are caused By nontoxic minerals that remain on the glass when the water evaporates. Spots on glass shower doors appear for the same reason. Commercial products are available that allow the water to drain from glassware more completely.

Q. What is a watershed?

A. A watershed is the region of land where all water drains-or "sheds"-to the same river, reservoir, or other body of water.