AgEBB-MU CAFNR Extension

David Burton
Civic Communications Specialist
2400 S. Scenic Ave.
Springfield, MO 65807

August 11, 2017

MU Extension Specialist Recommends Annually Testing Well Water for Bacterial Safety

MARSHFIELD, Mo. — Rural residents who get their water from private wells need to take steps to make sure their water supply is safe according to Bob Schultheis, a natural resources engineering specialist with University of Missouri Extension.

The best way to make sure water is safe is with an annual water test that monitors for bacteria and other contaminants that can make well water unhealthy.

"This inexpensive test can be obtained through your county's health department and can provide peace of mind for rural homeowners, or can alert them to a serious problem that needs correcting," said Schultheis.

Sample bottles for water tests, along with instructions, are available from the county health departments. Results are normally mailed back within seven to 10 days.

Schultheis responds here to the most common questions he receives on this issue.

Q: Protecting the safety of our drinking water is important, but difficult because of the fractured geology and cave structure underlying the Ozarks. How big of a problem is contamination of water wells in rural areas?

A: "Missouri Department of Health testing results show that, depending on the county, one-third to one-half of private water well systems in southwest Missouri are contaminated with coliform bacteria at unsafe levels," said Schultheis.

Q: What are some common ways water wells can get contaminated?

A: Failing septic systems located near the well are the biggest concern, especially if the well was drilled before 1987. Heavy rainfall flushing down sinkholes and losing streams, rapid housing development within a couple of miles of the well, and opening the plumbing system to make repairs are other common ways.

Q: How often should a private water well be tested for bacteria and what does it cost?

A: "The water should be tested at least annually, and preferably quarterly," said Schultheis. Sample bottles with instructions can be obtained from your county health department, and the testing costs $10 per sample. For most accurate results, keep the sample cool and away from light and get it to the lab within six hours of drawing it. Test results are returned to you within a week and should be kept with your important papers for liability purposes.

Q: If my well tests positive for bacteria, what can I do to correct it?

A: Shock-chlorination with ordinary, unscented laundry bleach or swimming pool chlorine tablets is often an inexpensive and effective way to correct the problem. After 7 to 10 days, the water should then be rechecked for bacteria. If the problem persists, other treatment options may be required.

Q: Where can I get more information on water testing and treatment options?

A: For information, contact the nearest University of Missouri Extension Center. Ask for MU Guides EQ100, 101, 102, and 103 from your county University of Missouri Extension Center, go online to or call Bob Schultheis at the Webster County Extension Center at 417-859-2044 for a step-by-step disinfection guide.

Source: Bob Schultheis, (417) 859-2044

Return to Current News Releases

MU Extension
College of Agriculture, Food, and Natural Resources
MU Extension Commercial Agriculture Program