Coliforms are bacteria that are naturally present in the environment and used as an indicator that other, potentially harmful, bacteria may be present. Coliforms found in more samples than allowed is a warning of potential problems.

Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5

Trihalomethanes occur when naturally-occurring organic and inorganic materials in the water react with the disinfectants, chlorine and chloramine.

Liver, kidney or central nervous system problems; increased risk of cancer

Haloacetic acids occur when naturally-occurring organic and inorganic materials in the water react with the disinfectants, chlorine and chloramine.

Increased risk of cancer

Nitrates and nitrites are nitrogen-oxygen chemical units which combine with various organic and inorganic compounds. The greatest use of nitrates is as a fertilizer. Once taken into the body, nitrates are converted to nitrites.

Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

1,1-Dichloroethylene is an organic liquid with a mild, sweet, chloroform-like odor. Virtually all 1,1-dichloroethylene is used in making adhesives, synthetic fibers, refrigerants, food packaging and coating resins such as the saran types.

Liver problems

Dichloromethane, also known as DCM and methylene chloride, is a volatile organic and colorless liquid chemical with a sweet, pleasant odor like chloroform. The greatest use of DCM is as a paint remover. Other uses include: solvent and cleaning agent in chemical manufacture, textiles, electronics, metals and plastics, pesticides industries; blowing and cleaning agent in the urethane foam industry; fumigant for strawberries and grains, and as degreener for citrus fruits; in pharmaceuticals and as an anesthetic; in extraction of caffeine, cocoa, fats, spices and beer hops; as a heat transfer agent in refrigeration products.

Liver problems; increased risk of cancer

Di(2-ethylhexyl) phthalate is the most commonly used of a group of related chemicals called phthalates or phthalic acid esters. The greatest use of di(2-ethylhexyl) phthalate is as a plasticizer for polyvinylchloride (PVC) and other polymers including rubber, cellulose and styrene. A number of packaging materials and tubings used in the production of foods and beverages are polyvinylchloride contaminated with phthalic aced esters, primarily di(2-ethylhexyl) phthalate.

Reproductive difficulties; liver problems; increased risk of cancer

1,2-Dichloropropane is a colorless flammable liquid with a chloroform-like odor. It does not occur naturally in the environment. It is used to make other organic chemicals. It is also used in making lead free gasoline, paper coating, soil fumigant for nematodes, and insecticide for stored grain.

Increased risk of cancer

Tetrachloroethylene is a colorless organic liquid with a mild, chloroform-like odor. The greatest use of tetrachloroethylene is in the textile industry, and as a component of aerosol dry-cleaning products.

Liver problems; increased risk of cancer

Ethylene bromide, also known as EDB, and 1,2-Dibromoethane, is a colorless, heavy synthetic organic liquid with a mildly sweet chloroform-like odor. Ethylene dibromide is mainly used in an anti-knock gasoline mixtures, particularly aviation fuel.

Problems with liver, stomach, reproductive system, or kidneys; increased risk of cancer

Carbon tetrachloride is a clear heavy organic liquid with a sweet aromatic odor similar to chloroform. Most carbon tetrachloride is used to make chlorofluorocarbon propellants and refrigerants, though this has been declining steadily. It has also been used as a dry cleaning agent and fire extinguisher; in making nylons; as a solvent for rubber cement, soaps, insecticides, etc.

Liver problems; increased risk of cancer

Chlordane, a synthetic organic chemical, is a viscous liquid, colorless to amber, with a slight chlorine-like aromatic odor. Chlordane was used in the past to kill a variety of insects. The only commercial use of chlordane products still permitted is for fire ant control in power transformers.

Liver or nervous system problems; increased risk of cancer

Barium is a lustrous, machinable metal which exists in nature only in ores containing mixtures of elements. It is used in making a wide variety of electronic components, in metal alloys, bleaches, dyes, fireworks, ceramics and glass. In particular, it is used in well drilling operations where it is directly released into the ground.

Increase in blood pressure

Chloramine (as CI2) is a water additive used to control microbes, particularly as a residual disinfectant in distribution system pipes. It is formed when ammonia is added to water containing free chlorine. Monochloramine is one form of chloramines commonly used for disinfection by municipal water systems. Other chloramines (di- and tri-) are not intentionally used to disinfect drinking water and are generally not formed during the drinking water disinfection process.

Eye/nose irritation; stomach discomfort, anemia

Antimony is a metal found in natural deposits such as ores containing other elements. The most widely used antimony compound is antimony trioxide, used as a flame retardant. It is also found in batteries, pigments, and ceramics/glass.

Increase in blood cholesterol; decrease in blood sugar

Benzene, a volatile organic chemical, is a clear, colorless aromatic liquid. It is highly flammable. It is formed through natural processes, such as volcanoes and forest fires. It is also formed from industrial processes. Benzene is also a natural part of crude oil, gasoline and cigarette smoke. The greatest use of benzene is as a building block for making plastics, rubber, resins and synthetic fabrics like nylon and polyester. Other uses include: as a solvent in printing, paints, dry cleaning, etc.

Anemia; decrease in blood platelets; increased risk of cancer

Beryllium is an inorganic metallic element in the periodic table. Because it is an element, it does not degrade nor can it be destroyed. Compounds of beryllium are either white or colorless and do not have a particular smell. The greatest use of beryllium is in making metal alloys for nuclear reactors and the aerospace industry. Other uses are as an alloy and oxide in electrical equipment and microwave ovens.

Intestinal lesions

Arsenic is a semi-metal element in the periodic table. It is odorless and tasteless. It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. Approximately 90 percent of industrial arsenic in the U.S. is currently used as a wood preservative, but arsenic is also used in paints, dyes, metals, drugs, soaps, and semi-conductors. Agricultural applications, mining, and smelting also contribute to arsenic releases in the environment.

Skin damage or problems with circulatory systems, and may have increased risk of getting cancer

1,2-Dichloroethane is a colorless, oily, organic liquid with a sweet, chloroform-like odor. The greatest use of 1,2-dichloroethane is in making chemicals involved in plastics, rubber and synthetic textile fibers. Other uses include: as a solvent for resins and fats, photography, photocopying, cosmetics, drugs, and as a fumigant for grains and orchards.

Increased risk of cancer

Vinyl chloride is a colorless organic gas with a sweet odor. Vinyl chloride is used in the manufacture of numerous products in building construction, automotive industry, electrical wire insulation and cables, piping, industrial and household equipment, medical supplies, and is depended upon heavily by the rubber, paper, and glass industries.

Increased risk of cancer

Trichloroethylene, a volatile organic chemical, is a colorless or blue liquid with a chloroform-like odor. Trichloroethylene is primarily used to remove grease from fabricated metal parts and in the production of some textiles.

Liver problems; increased risk of cancer

Chlorite occurs when chlorine dioxide breaks down.

Anemia; infants & young children: nervous system effects

Chlorine dioxide is a water additive used to control microbes and can be used to control tastes and odors. It rapidly disappears from stored water.

Anemia; infants & young children: nervous system effects

Toxaphene, a synthetic organic chemical, is an amber, waxy organic solid with a piney odor. Toxaphene was used as an insecticide for cotton and vegetables, and on livestock and poultry. In 1982, most of its uses were banned and in 1990, all uses were banned in the United States.

Kidney, liver, or thyroid problems; increased risk of cancer

Thallium is a metal found in natural deposits such as ores containing other elements. The greatest use of thallium is in specialized electronic research equipment.

Hair loss; changes in blood; kidney, intestine, or liver problems

cis-1,2-Dichloroethylene is an odorless organic liquid that has two slightly different forms, a cis form and a trans form. Both the cis and trans forms – usually as a mixture – are used as a solvent for waxes and resins; in the extraction of rubber; as a refrigerant; in the manufacture of pharmaceuticals and artificial pearls; in the extraction of oils and fats from fish and meat; and in making other organics.

Liver problems

Cadmium is a metal found in natural deposits such as ores containing other elements. Cadmium is used primarily for metal plating and coating operations, including transportation equipment, machinery and baking enamels, photography, and television phosphors. It is also used in nickel-cadmium solar batteries and pigments.

Kidney damage

Selenium is a metal found in natural deposits such as ores containing other elements. The greatest use of selenium compounds is in electronic and photocopier components, but they are also widely used in glass, pigments, rubber, metal alloys, textiles, petroleum, medical therapeutic agents, and photographic emulsions.

Hair or fingernail loss; numbness in fingers or toes; circulatory problems

Fluoride compounds are salts that form when the element, fluorine, combines with minerals in soil or rocks. Many communities add fluoride to their drinking water to promote dental health.

Bone disease (pain and tenderness of the bones); Children may get mottled teeth