Water Quality

Drinking Water Standards & Testing



E. Coli

  • E. coli is a type of fecal coliform bacteria commonly found in the intestines of animals and humans. E. coli is short for Escherichia coli. The presence of E. coli in water may indicate sewage or animal waste contamination.​​

Heterotrophic Plate Count (HPC)

  • HPC has no health effects. It is a test method used as an indicator for pathogens.​

Total Coliforms

  • Charlotte Water must analyze first for total coliform because this test is faster to produce results. Any time that a sample is positive for total coliform, the same sample must be analyzed for either fecal coliform or E. coli.​


  • Turbidity refers to the cloudiness of water. Turbidity has no health effects, but can interfere with disinfection and provide a medium for microbial growth. Turbidity is measured in Nephelometric Turbidity Units or NTU's.​



  • ​​The gaseous or liquid form of chlorine (Cl2) is a water additive used by Charlotte Water to control microbes as drinking water travels from the plant to our customers. ​

Disinfection Byproducts (DBP)

​​Total Trihalomethanes (TTHM) 

  • Trihalomethanes occur when naturally occurring organic and inorganic materials in the water react with the disinfectants. THM levels are influenced by temperature, pH, and water age primarily. TTHM is reported as the Locational Running Annual Average or LRAA. ​

Haloacetic Acids (HAA5)

  • Haloacetic acids occur when naturally occurring organic and inorganic materials in the water react with disinfectants.HAA5 is reported as the Locational Running Annual Average or LRAA. ​

​Inorganic Chemicals


  • Antimony is a metal found in natural deposits such as ores containing other elements and is often used as a flame retardant.​


  • 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. Ninety percent of arsenic in industrial uses is found in wood preservatives.​


  • Barium 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.​


  • ​The greatest use of beryllium is in making metal alloys for nuclear reactors and the aerospace industry.​


  • Cadmium is used primarily for metal plating and coating operations, including transportation equipment, machinery and baking enamels, photography, and television phosphors. It can also be found in batteries.​

Chromium (Total)

  • Chromium is naturally occurring. Some forms of chromium are found in multi-vitamins. Other forms of chromium can be harmful at certain levels. Total chromium measures all forms of chromium together.​​


  • ​Fluoride is a mineral that occurs naturally in virtually all waters. Fluoride has also been proven to promote oral health. on the recommendation of the American Dental Association, Charlotte Water adds fluoride to drinking water so that the target concentration is 0.7 mg/L or less than 1 part per million.​


  • Iron is naturally occurring. It is also considered a Secondary Drinking Water contaminant to assist in managing drinking water for taste, color, or odor. It is not considered a human health risk but may indicate at certain levels undesirable water for customers.​


  • ​​Lead is naturally occurring but can also be found in plumbing as pipe material and as a component of solder. Lead was banned in 1986 from being installed in public water systems or any plumbing providing water for human consumption connected to a public water system. In 1991, the EPA established a maximum contaminant level goal of zero for lead in drinking water.​


  • ​Nitrate is a form of nitrogen often found in fertilizers.​


  • Nitrite is a form of nitrogen that can be found in the medical, agricultural and food production industries primarily.​


  • The greatest use of selenium compounds is in electronic and photocopier components​.


  • The greatest use of thallium is in specialized electronic research equipment​.

Ammonia as Nitrogen

  • ​Ammonia is a form of nitrogen with many uses including fertilizers, cleaners, and a fermenting agent.​

Total Calcium 

  • ​The greatest use of thallium is in specialized electronic research equipment​.

Hardness (by calculation) as Calcium Carbonate​

  • ​​Hardness in drinking water is caused by two nontoxic chemicals-the minerals calcium and magnesium. If either of these minerals is present in your water in substantial amounts, the water is said to be hard, because making a lather or suds for washing is hard (difficult) to do. Water containing little calcium or magnesium is called soft water. ​

Organic Chemicals


  • Benzene is formed through natural processes, such as volcanoes and forest fires. It is also formed from industrial processes. Benzene is also found in crude oil, dry-cleaning solvents, gasoline, and cigarette smoke.​

Carbon Tetrachloride

  • 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.​


  • ​Chlorobenzene is used in the manufacture of other organic chemicals, dyestuffs, and insecticides. It is also used a solvent for adhesives, drugs, rubber, paints, and dry cleaning.​


  • This compound is typically used in agricultural applications to manage pests.​


  • The greatest use of 1,2-dichloroethane is in making chemicals involved in plastics, rubber, and synthetic textile fibers.​ 


  • Virtually all 1,1-dichloroethylene is used in making adhesives, synthetic fibers, refrigerants, food packaging and coating resins such as the saran types.​


  • Dichloromethane is most often used as a paint remover.​


  • 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.​


  • The greatest use — more than 99 percent — of ethylbenzene is to make styrene, another organic liquid used as a building block for many plastics.​


  • The largest chemical use for toluene is to make benzene and urethane​.


  • The greatest industrial use of trichlorobenzene is as a dyeing agent.​


  • It is largely used as a solvent removing grease from machined metal products.​


  • ​Trichloroethylene (also known as TCE) is primarily used to remove grease from fabricated metal parts and in the production of some textiles. It was once used as a dry cleaning solvent.​


  • Xylenes are often used to make polyester fiber and film. It can also be found in gasoline.

Vinyl Chloride

  • 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.​​​