Testing Well Water for Microbiological Contamination


New wells should be disinfected by the well driller at the time of construction to eliminate any microbiological contamination that may have occurred during drilling. This should be done before collecting a sample for microbiological testing. Existing wells should be tested two or three times a year. The best time to sample your well water is when the probability of contamination is greatest. This is likely to be in early spring just after the thaw, after an extended dry spell, following heavy rains or after lengthy periods of non-use.

Depending on the province, bacteriological testing of well water is done either by the provincial health laboratory in your area or by a certified private laboratory. They will supply you with a clean, sterile sample bottle and the necessary instructions. Samples collected in any other container will not yield meaningful results and will not be accepted by the laboratory. In all instances, samples should be refrigerated immediately and transported to the laboratory within 24 hours.

If you have experienced gastrointestinal illness and suspect that it might be associated with your well water, consult your physician and local health unit.

Well Maintenance

Interpreting the Results of Testing

Corrective Action for Water that Does Not Meet the Recommended Guidelines

Water Treatment Devices for Home Use

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