Is E. coli Common in Well Water?

One of the most common calls we get at the lab is from people worried that their well water might have E. coli in it.

E. coli is what’s called a coliform bacteria. Coliforms are a group of bacteria commonly found in the environment and in animal feces. Many coliform bacteria aren’t harmful on their own, but they mean your water is contaminated and could also contain other bacteria, viruses, or pathogens.

E. coli is a bacteria that specifically comes from the intestines of animals. That means your drinking water has come into contact with animal feces. Besides being unpleasant to think about, E. coli can cause serious illness and gastrointestinal issues.

Is E. coli common in well water?

Unfortunately, yes. It’s one of the most common problems we see at our laboratory. A study by the North Carolina Department of Health found that about 2% of private wells tested positive for E. coli. 2% might not sound large, but that means that nearly 460,000 wells across the US would test positive for E. coli.

But E. coli doesn’t just appear out of nowhere. It’s often a sign of another issue, like surface water runoff getting into the well, a cracked well casing, or a damaged or missing well cap. That’s why it’s important to routinely test for coliform bacteria in e coli.

Because E. coli is commonly found in well water and potentially dangerous, what can you do to protect your family?

The only way to know for sure if you water is e coli free is to test. Our DIY Bacteria Test Kit makes this easy, you simply fill the vial with water and watch for a color change. It can detect 50 species of coliform bacteria, including E. coli.

Because bacteria is often an early warning sign of bigger problems, we recommend testing quarterly, especially if you rely on a private well.

 

If your well water tests positive for E. coli, what should you do?

 

The first step is to stop drinking it and cooking with it, and switch to bottled water.

Next, the well needs to be shock chlorinated.

Some homeowners are comfortable doing this themselves using a guide, but many choose to hire a professional. After chlorination, wait one to two weeks and then test again.
If the water still tests positive, that’s a sign of a chronic issue and a professional should inspect the well to find the source of contamination.