Article: Signs Your Private Well Has Been Contaminated After a Storm

Heavy rain, flooding, and severe storms can dramatically change the quality of groundwater and the condition of private wells. While wells are designed to protect water supplies from surface contamination, the natural environment becomes unpredictable during storms. Floodwaters, runoff, and shifting soil can introduce bacteria, chemicals, and debris that alter the safety of your water without any visible warning. After a major weather event, it is critical to assess whether your well water may have been compromised. Understanding the signs of contamination helps you take appropriate action before drinking or using the water.

One of the most common indicators of storm-related contamination is a sudden change in the appearance of your water. If the water turns cloudy, murky, discolored, or contains visible sediment, this suggests that runoff has entered the well. Stormwater often carries soil, organic matter, and microorganisms, and when this mix infiltrates a well, it usually shows up as turbidity in the water. Even if the water clears after a short period, the contamination may still persist at a microbial level.

Another strong sign of well contamination is a noticeable change in taste or odor. If your water suddenly develops a musty, earthy, metallic, or unpleasant smell after a storm, it may indicate the presence of bacteria, decaying organic material, or chemical intrusion. Wells located near agricultural areas, septic systems, or livestock operations are particularly vulnerable because runoff from these sites may contain pathogens or nitrates. Changes in taste or odor are never something to ignore after a severe weather event.

Storms can also physically damage the well structure, allowing contaminants to enter. A cracked or loose well cap, damaged casing, or displaced electrical conduit can let surface water flow directly into the system. Even minor structural issues can compromise the well’s protective barrier. After a storm, it is wise to visually inspect the well for signs of physical damage, erosion, or pooling water around the casing. If the area around the well was submerged, there is a high chance of bacterial intrusion.

Another signal of contamination is a drop in water pressure or the presence of air in your taps. Storms can disturb the aquifer or introduce debris that partially blocks the pump or plumbing system. Pressure fluctuations may also indicate that water levels have temporarily changed due to flooding or infiltration. While pressure changes alone do not prove contamination, they often accompany it and should not be dismissed.

Illness in the household following a storm is a serious warning sign. Gastrointestinal symptoms including nausea, cramps, diarrhea, or fever may indicate exposure to bacteria such as E. coli or coliforms. Because these organisms can enter wells during flooding or heavy rain, it is important to stop using the water immediately and perform a bacteria test before continuing.

Even if none of these signs appear, well water should still be tested after a major storm. Contamination is frequently invisible and odorless. A well can test completely clean one day and unsafe the next due to shifting groundwater conditions. Testing for bacteria is the first step, but follow-up testing for nitrates, chemicals, or heavy metals may also be necessary depending on the severity of the storm.

The safest approach after a major weather event is to assume the water may be unsafe until testing proves otherwise. If contamination is confirmed, disinfection, shock chlorination, and system flushing may be required. Once corrective steps are taken, repeat testing verifies that the well has returned to a safe condition.

Storms are unpredictable, but your water safety doesn’t have to be. Knowing the signs of contamination and testing promptly protects your household from the hidden dangers that often follow extreme weather.

By Ryan N., PhD