If your well tests positive for E. coli, you should boil the water for at least one minute at a rolling boil before drinking it. E. coli contamination means that fecal matter has entered your water supply, which is a serious health hazard. Children, elderly individuals, pregnant women, and anyone with a compromised immune system are especially vulnerable. Immediate action is required to protect your family's health and eliminate the contamination from your well system.
Immediate Steps to Take
First, stop using the water for drinking, cooking, brushing teeth, or preparing baby formula. Switch to bottled water or boil all water for at least one minute at a rolling boil before use. Do not rely on filters—standard sediment or carbon filters cannot remove bacteria. If you have a whole-house UV disinfection system, verify that it's functioning properly, but still use boiled or bottled water until follow-up testing confirms the E. coli has been eliminated.
Identify and Fix the Source
Before disinfecting your well, a professional must inspect the well's physical condition to identify how E. coli entered. Common pathways include a cracked or loose well cap, damaged casing, a wellhead that sits below ground level where water pools, compromised electrical conduit seals, and recent flooding or construction activity that disturbed the well's protective barriers. The source must be fixed before disinfection, or the bacteria will simply return.
Shock Chlorination Process
Professional shock chlorination involves introducing a calculated concentration of chlorine into your well and plumbing system. The chlorine must contact all surfaces for 12 to 24 hours to kill all bacteria. After the contact period, the entire system is thoroughly flushed until chlorine levels drop below the EPA safe drinking water standard. This process requires expertise—too little chlorine won't kill all bacteria, while too much can damage your pump and plumbing.
Follow-Up Testing
After shock chlorination, wait 7 to 10 days and then test your water again. Only when the follow-up test shows "absent" for both total coliform and E. coli should you resume normal water use. If the test is still positive, a second shock treatment may be needed, or there may be a persistent contamination source that requires more extensive repair.
Has your well tested positive for bacteria? Call 77 Water Well Inc. at (281) 456-4556 for emergency inspection, shock chlorination, and water testing.