An estimated 15 million families drink water from private, unregulated wells, and 2 million of those from wells that fail to meet the federal drinking water standards for nitrate. Nitrate and nitrite are two chemicals found in private well water. Infants less than one year old that ingest elevated levels from baby formula prepared with contaminated well water can develop cyanosis or "blue baby syndrome;" a serious illness that can cause brain damage or death. The nitrate MCL is 10 ppb; nitrite is 1 ppb.

      The presence of coliform bacteria is an indicator of pathogenic organisms that cause disease. Some strains of E. Coli cause serious illness and death. A positive result for E. Coli indicates there are defects in the well or plumbing, allowing entry of animal manure or sewage waste.

1.   Arsenic - Once widely used as an insecticide, herbicide or wood preservative, is a known human carcinogen. The EPA recently reduced the allowable MCL (Maximum Contaminant Level), in drinking water from 50 ppb (parts per billion), to 10 ppb.
   
   
2.   Cadmium - Highly toxic. Could be leached into well water from corroded galvanized pipes. Has a very low (5 ppb), MCL. Causes kidney damage.
   
   
3.    Copper - Short-term exposure causes gastrointestinal distress; long-term exposure causes liver or kidney damage. The drinking water MCL is 1.3 ppm (parts per million). Contamination could occur from corroded plumbing, or copper sulfate; commonly referred to as "Bluestone", added to septic systems or cattle ponds to deter algae growth. Cattle and sheep are most susceptible to excess Cu: For cattle, the Cu tolerance limit is < 100 ppm and for sheep it's < 25 ppm.
   
   
4.    Lead - Highly toxic. Can be leached from corroded plumbing, improper disposal of lead batteries or erosion of natural deposits. Causes mental developmental problems in children. The drinking water MCL is 15 ppb.
   
   
5.    Mercury - Highly toxic, causes major changes in the brain including loss of vision, hearing, intellectual deterioration and kidney damage. Can be leached from landfills, agricultural usage, industrial plants or erosion of natural deposits. The drinking water MCL is 2 ppb.
   
   
6.    Iron - A secondary contaminant. Causes objectionable taste, odor or staining. An SMCL (secondary contaminant level), of 300 ppb may cause animals, especially cows; to not drink enough water. Dairy cows may not achieve optimum milk production if water is high in iron.
   
   

1.   Fluoride - Found naturally in groundwater, or erosion of natural deposits, (Fluorspar mineral formations in Texas counties). May stain permanent teeth in children above 1.8 ppm; causes bone disease or bone pain and tenderness at levels above the 4.0 ppm MCL.
   
   
2.   Sulfate - A secondary contaminant that occurs widely in groundwater, easily dissolved from soils and rock. The SMCL limit is 250 ppm. Higher levels than 250 ppm are likely to cause diarrhea in humans and animals. Sulfate can also cause hard scale to form in hot water heaters.
   
   

1.   New Report outlines Dangers of Well Water In Infant Nitrate Poisoning. American Academy of Pediatrics. (September, 2005). Online version available at:
   http://www.aap.org/advocacy/releases/sept05wellwater.htm
   
   
2.   Kross BC, Avebo AD, Fuortes LJ. (1992) Methemoglobinemia: nitrate toxicity in rural America. American Family Physician. July 1992; Vol 46(No.1), pp183-8. Online version available at:
   http://www.ncbi.nlm.nih.gov/pubmed/1621630
   
   
3.    Bradshaw MH, Powell MG, Understanding Your Water Test Report, Kansas State University, (January 2000). Online at:
   http://www.ksre.ksu.edu/library/h20ql2/MF912.PDF
   
   
4.    McDowell LR, (2003). Minerals in Animal and Human Nutrition. Elsevier Health Services. Edition 2. pp267-269. Online at:
   http://books.google.com/books?isbn=0444513671