Water wells can be contaminated by flooding. This contamination may involve an unpleasant taste, odour, or cloudiness of the well water, but some contamination, like bacteria, can only be recognized after water quality testing.

Under flood conditions, surface water may enter directly into the water source via the well itself, an old abandoned well, or some other nearby excavation, bypassing the natural filtering process. Testing and recovery efforts should be focused on possible bacterial contamination.

Ensure well water is safe to use

While the majority of water wells are likely unaffected, each homeowner should take certain steps to ensure their well water is safe to use for drinking, cooking and/or bathing. As a first step, a flooded well should be disinfected once the flood waters immediately around the well have gone away. Chlorination is a procedure used to disinfect a water well contaminated with bacteria.

For instructions on how to disinfect your well visit Fact Sheet: Private Well Disinfection Instructions.

Water testing

Water from all wells in the flooded area should be tested for quality. In order to do this, you should pick up a water sample bottle from Renfrew County and District Health Unit (RCDHU). Wait at least 2 days after disinfecting the well to collect a water sample to make sure that the chlorine disinfectant is out of the well. Do not collect a water sample until the chlorine is gone.

To consider the well water safe to drink, RCDHU recommends that you get three good tests taken 2-4 weeks apart.

Until testing shows your well water to be safe, all well water for drinking, cooking and bathing should be boiled. Bringing water to a rolling boil for 1 minute will kill most organisms. If you suspect or are informed that the water is contaminated with chemicals, seek another source of water immediately, such as bottled water. Boiling water does not remove chemical contaminants.

If water testing indicates that your water well has some level of contamination, then the well should be chlorinated and retested.

Some water wells will be unaffected by floodwater and not be contaminated. However, all wells should still be tested three times per year to monitor for contamination. A contaminated well may have to be chlorinated more than once. Do not drink, or cook with this water until a clean sample result is obtained.

For more information, please call RCDHU at 613-732-3629, extension 505.