May 15, 1995

PRIVATE WATER WELL STUDY FINDS NEARLY ONE-THIRD ARE CONTAMINATED

SPRINGFIELD, IL -- A review of 130,000 private water well samples analyzed by the Illinois Department of Public Health's laboratories from 1986 through 1994 has found a significant number contained bacterial contamination, Dr. John R. Lumpkin, state public health director, announced today.

Dr. Lumpkin called on homeowners who get their drinking water from private wells to have the water tested for bacteria.

"Although there does not appear to be an imminent health threat to the more than 1 million people in Illinois who rely on private wells for their water, bacteria can cause serious health risks, particularly to infants and immune compromised people, such as cancer patients or persons with AIDS," Dr. Lumpkin said. "These risks can include persistent diarrhea, nausea or vomiting."

Dr. Lumpkin urged private well owners to take the following precautions:

• Have the water tested at least once a year for bacterial contaminants and, if contaminated, disinfect the well and have a second sample taken. If a second sample tests positive for bacteria, the well owner should arrange a site visit by a local health department sanitarian to check for construction or location defects.
• If anyone in the household has a chronic illness, weakened immune system or is under 6 months of age, they should use an alternative source of water (such as bottled water or that from a municipal water system) until the well water has been tested and determined safe to drink.

Of the 129,257 private water wells sample submitted to the Department over the nine-year period, 27 percent, or 34,829, tested positive for coliform bacteria. The presence of coliform bacteria indicates contamination from soil or surface water.

A band of 29 counties, located mostly in the central part of the state, had the highest percentage of contaminated wells, with more than 40 percent of those tested having bacterial contamination. Schuyler County had the largest percentage of contaminated wells (60.5%), followed by Edgar (59.3%), Cumberland (58.8%) and Clark (58%) counties.

The reason this part of the state has high contamination rates is most likely the result of the hydrogeological conditions. The area's underground source of water is shallow and the wells used to tap the water are more susceptible to surface water contamination.

Another 37 counties had bacterial contamination rates of between 20 percent and 40 percent of all samples analyzed (see attached map and charts).

Counties with less than 10 percent of the wells contaminated were DeKalb (5.7%), Cook (7.3%), Will (7.4%), Whiteside (8%), Kane (8.2%), Union (9.6%) and Kendall (9.9%).

Well contamination could be the result of poor well or water system construction, maintenance, location, accidents, repairs with no follow-up disinfection or a combination of these.

No matter what the rate of contamination reported by this study, Dr. Lumpkin said the water well should be tested annually.

Private well users can call the Department's toll-free water well hotline, 1-800-545-2200 (TTY 1-800-547-0466, hearing impaired use only) for information and assistance about how to have a well sampled or disinfected. For testing, callers will be given the number of the local health department where they live to obtain a state-supplied test sample kit or, if they are not served by a local health department, the Department's nearest regional office.

The Department will test water samples submitted to local health departments or regional offices at a cost of $10, plus any handling costs the local health department may charge. Some local health departments and private laboratories also can do water well analyses.

For those who have contaminated wells, copies of a 10-minute VHS videotape developed by the Department about how to disinfect a water well are available at public libraries and local health departments. The videotape is closed captioned for the hearing impaired.

Dr. Lumpkin said a statewide private water well quality study in 1994 of 818 private drinking-water wells funded by the U.S. Centers for Disease Control and Prevention (CDC) led the Department to review historical data on well contamination. The CDC survey found that more than four out of 10 wells tested had bacterial contamination.

The CDC has provided the Department with $87,600 to do a follow-up study of about 400 private water wells in the state that will begin in June. The results are expected to be available later this year.

Illinois Department of Public Health 535 West Jefferson Street Springfield, Illinois 62761 Phone 217-782-4977 Fax 217-782-3987 TTY 800-547-0466 Questions or Comments