Health Effects Information
On December 6, 1974 the Safe Drinking Water Act (SDWA) was signed into law. The purpose of the law is to assure that the nation's water supply systems serving the public meet minimum national standards for the protection of public health. The SDWA covers all public water systems with piped water for human consumption with at least 15 service connections or a system that regularly serves at least 25 individuals.
The SDWA directed the U.S. Environmental Protection Agency (EPA) to establish national drinking water standards. These standards limit the amount of certain contaminants provided by public water. Food and Drug Administration (FDA) regulations establish limits for contaminants in bottled water. All drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that the water poses a health risk.
The water delivered to you must meet strict rules of purity. In the Water Quality Report (pdf) , you see the MCL's expressed in parts per billion. Have you ever heard the expression, "to win the publisher clearing house sweepstakes is a one chance in a million? Nearly everyone has difficulty understanding what one in a million actually means. In the drinking water industry we take the concept of one in a million very seriously, since this is how we measure very small traces of chemicals or contaminants in water. When we test and measure the level of contaminants in water, we record and report the results in terms of - parts per million, or milligrams per liter, written as ppm or mg/l respectively. A smaller unit of detection we regularly use is parts per billion, or micrograms per liter, written as ppb or µg/l.
One part per million, or one milligram per liter, would be equal to putting ONE drop of water into 10 gallons of water. One part per billion, or one microgram per liter, would be equal to adding one drop of water to a 10,000 gallon swimming pool. (A part per billion is 1,000 times smaller than a part per million.)
To better understand the possible health effects that are described below for regulated contaminants, a person would have to drink 2 liters, (a little more than two quarts), of water every day at the Maximum Concentration Level (MCL) for a lifetime, (which at present is about 70 to 80 years), to have a "one in a million chance" of having the described health effect.
Arsenic - Some people who drink water containing arsenic in excess of the MCL (50 parts per billion) over many years could experience skin damage or problems with their circulatory system and may have an increased risk of getting cancer.
Barium - Some people who drink water containing barium in excess of the MCL (2000 parts per billion) over many years could experience an increase in their blood pressure.
Benzene - Some people who drink water containing benzene in excess of the MCL (5 parts per billion) over many years could experience anemia or a decrease in blood platelets, and may have an increased risk of getting cancer.
Chromium - Some people who drink water containing chromium well in excess of the MCL (100 parts per billion) over many years could experience allergic dermatitis.
COPPER: Copper is an essential nutrient, but some people who drink water containing copper in excess of the action level (1300 parts per billion) over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney damage. People with Wilson's Disease should consult their personal doctor.
Lead - Infants and children who drink water containing lead in excess of the action level (15 parts per billion) could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink this water over many years could develop kidney problems or high blood pressure.
Nitrate - Infants below the age of six months who drink water containing nitrate in excess of the MCL (10,000 parts per billion) could become seriously ill and, if untreated may die. Symptoms include shortness of breath and bluebaby syndrome.
Total Trihalomethanes - Some people who drink water containing TTHM's in excess of the MCL (80 parts per billion) over many years may experience problems with their liver, kidneys, or central nervous systems, and may have an increased risk of getting cancer.
Please see Water Contaminants for additional information.