Most Private Wells Don't Meet Safe Drinking Water Standards
A recent survey of private wells in the Midwest found that on average for Kansas, 60 percent of all wells sampled and 80 percent of dug (versus drilled) wells did not meet the same safe drinking water standards used for public systems.
"There are about 120,000 private wells in Kansas and 1,500 new ones are drilled each year," said Kansas State University water quality specialist Morgan Powell.
Well maintenance and common sense are key to ensuring a safe water supply, said Powell. "You don't just check the oil on your car - you change it periodically and do regular maintenance to keep it running properly."
The same approach should be applied to wells, he said. Wells should be located above and away from possible sources of contamination and constructed to meet current state health and environmental standards. Then, establishing and following a maintenance plan is key to assuring a safe drinking water supply.
Surveys conducted in Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota and Wisconsin in 1994-95 also found that potential contamination sources were commonly found within 100 feet of the well head. Septic tanks, lateral fields and other structures that contain human or animal feces were the most common potential polluting sources.
"Out of sight, out of mind," was how Powell described some well owners' attitudes toward preventive maintenance.
Powell related the story of a woman's trips to the doctor for chronic flu symptoms. Her pharmacist suggested maybe her well water was the culprit, rather than the flu. He was right.
Powell recommends these checkpoints for annual well maintenance:
- Check the well casing for cracks and leaks;
- Check the well cap for water tightness;
- Ensure the ground surface is sloped away from the well for 15 feet in all directions;
- "Shock chlorinate" the well and water system if testing indicates a bacteria contamination problem - a procedure in which a strong dose of chlorine (500 parts per million) is flushed through the system, and then held for at least 12 hours, to kill bacteria;
- Test for coliform bacteria, nitrate, pH and total dissolved solids. File results with other records on the well;
- Make sure a protection plan is in place and is being followed.
Well owners should establish a "zone of exclusion" around every well, Powell said. That "zone" or circle should be in a 100- to 200-foot radius from the well and no buildings or storage of any kind of polluting liquid - even temporary - should fall within that circle. Dry material storage also is discouraged in this area. However, if necessary, a dose of protection could be secondary containment of the material. Beyond that there should be a "management zone" with a total radius of 200 to 400 feet in which any liquid storage is protected by secondary containment and dry material is managed carefully. Any spills should be cleaned up in this area.
