Frequently Requested Water Contaminant Definitions

Alkalinity is the measure of water’s ability to neutralize acids. Alkalinity can be affected by natural deposits in the earth and industrial practices. It is not considered to be hazardous to health. The recommended level of alkalinity in well water in potable water is between 75 to milligrams (mg)/ 1 liter (L) of calcium carbonate (Ca(03).

 

Arsenic is a semi-metal element that is odorless and tasteless. It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. The maximum allowable level of arsenic in potable water is less than 10 micrograms (ug)/ 1 liter (L) of water.

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Coliform bacteria are a common bacteria that is found naturally in human and animal feces, as well soil, submerged wood, and other organic matter. Total coliforms are used as an indicator of bacteriological contamination in drinking water from outside sources, but may not be harmful. The acceptable level for coliform bacteria in potable water is 0 coliforms/100 milliliters (ml) of water. The coliform test is a presence/absence analysis and therefore the results are indicated as positive/negative for coliform bacteria.

Copper is a common metal that occurs naturally in the environment, and may be used in agricultural applications or industry. Short-term effects of drinking water with an excess of copper include vomiting, diarrhea and other stomach discomfort. Long-term exposure can have serious health implications, such as liver or kidney damage. The EPA’s recommended Maximum Contaminant Level of copper in potable water is less than 1.3 milligram (mg)/ 1 liter (L) of

E. coli bacteria is a common form of bacteria occurring in the fecal matter of healthy warm-blooded animals, such as humans. Although most strains of E. coli are harmless, its presence in water can indicate fecal or sewage contamination that may cause illness. The acceptable level for f. coli bacteria in potable water is 0 coliforms/100 milliliters (ml) of water. The E. coli test is a presence/absence analysis and therefore the results are indicated as positive or negative for E. coli bacteria.

Fluoride is a common element naturally found in surface and ground water. Additional fluoride enters drinking water from agricultural and industrial sources. According to the U.S. EPA, exposure to elevated levels of fluoride over a lifetime can result in an increased risk of bone fractures and cosmetic effects on teeth. The EPA’s recommended Maximum Contaminant Level of fluoride in potable water is less than 4 milligrams (mg)/ 1 liter (L) of water.

Hardness is the measure of water’s ability to react with soap and produce a lather. Minerals such as calcium and magnesium are some of the more common ions that enter water supplies from sedimentary rocks and soils, causing hardness in water. Hard water requires more soap to create a lather, and may leave mineral deposits on fixtures. It is not considered hazardous to health.

Iron is a metal element that makes up about 5% of the earth’s crust. It is not considered hazardous to health. To avoid aesthetic concerns, such as staining of fixtures, water appearance and taste, the recommended level of iron in potable water is less than 0.3 milligrams (mg)/ 1 liter (L) of water.

Lead is a toxic metal that was used in products located in and around homes. It typically enters drinking water supplies from the corrosion of plumbing systems. The maximum allowable level of lead in potable water is less than 15 micrograms (ug)/ 1 liter (L) of water.

Manganese is a common element that is naturally occurring in the earth’s crust. According to the U.S. EPA, exposure to elevated levels of manganese can cause headaches, mood changes, insomnia, and weakness. Long-term exposure at elevated levels may result in nervous-system disorders. The maximum recommended level of manganese in potable water is less than 50 micrograms (µg) / 1 liter (L) of water.

Nitrate is a form of nitrogen that can reduce the amount of oxygen in the blood of infants under six months old. Nitrate is a commonly used lawn and agricultural fertilizer and can also be formed in the decomposition of waste materials. The maximum allowable level of nitrate in potable water is less than 10 milligrams (mg)/ 1 liter (L) of water.

The R.!::!. of water is a measure of the acid-base balance. Carbon dioxide concentration and increases in temperature can decrease the pH of water. A pH of 7 is considered neutral, while a pH of less than 7 is considered acidic, and a pH of more than 7 is considered basic.