T. Coliform & E. Coli Test

Bacteria in Your Well Water: What You Need to Know

Coliform bacteria are microorganisms found in the environment, in soil, and in the digestive tracts of humans and animals. Finding coliform in your drinking water is a red flag. While coliform bacteria themselves may not always cause illness, their presence strongly suggests that other harmful pathogens have found their way into your water supply. The EPA uses total coliform as the standard measure of water sanitation for exactly this reason.

For private well owners, coliform and E. coli contamination is one of the most common water quality problems and one of the most important to catch early. It can enter a well through cracks in the casing, surface water runoff, nearby septic systems, flooding, animal activity around the wellhead, and even insect infestations through unsealed or damaged well caps. Homes on shallow or dug wells face a significantly higher risk of coliform and E. coli contamination due to their proximity to surface water and soil.

Households near lakes or wetlands are also at considerably greater risk. Surface water from these sources can infiltrate groundwater and introduce bacteria into private wells, making regular well disinfection, testing, and filtration especially important for anyone in these areas.

High bacteria levels in well water can sometimes be accompanied by a smell of rotten eggs, sulfur, or a general foul odor. If your water has developed an unusual smell, it is important to test right away and confirm that regular well disinfection is being performed. Do not ignore odor changes in your water.

Wells also function best when used consistently. If you are returning to a vacation home on well water or coming back to your regular home after an extended time away, retesting for coliform and E. coli is strongly recommended. Stagnant well water that is not being regularly replenished by fresh water from the aquifer creates conditions where bacteria can replicate rapidly, leading to elevated counts that would not otherwise be present.

How It Works

Order your test and we will mail you a sample collection kit with easy-to-follow instructions. Collect a water sample from your tap and send it back to our lab. This test is completed within 24 hours of arriving at our lab with results delivered within 1 to 2 business days.

Understanding Your Results

A positive coliform result does not always mean your water is dangerous, but it does mean something needs attention. Every test includes a free consultation with one of our in-house water quality experts. Once your results are in, our team is available by phone or email to walk you through exactly what was found and what it means. If any action is needed, whether that is well chlorination, a well inspection, or follow up testing, we will point you in the right direction.

This test is recommended for private well owners as part of routine annual testing, homebuyers who want to confirm the biological safety of their water before closing, households near lakes or wetlands, owners of shallow or dug wells, anyone returning to a home after an extended absence, and any household where people or pets have experienced unexplained illness that could be water related.