It is recommended that you test your well water regularly for the indicator bacteria total coliforms and E. coli.
If present, it is an indication that the water may contain harmful micro-organisms that can make you sick.
Testing at least three times a year for bacteria is recommended by the Ontario Ministry of the Environment and the Ontario Ministry of Health and Long-Term Care.
Early spring is a good time to test your well water for bacteria. Another good time is the day after a heavy rainfall. Melting snow and running water can carry surface contaminants into your well water. If your well water is safe under these conditions, it is most likely to be safe the rest of the year.
Test your water even if your water seems fine, because you can not always taste, smell or see bacteria or other contaminants. Do not rely on your neighbour’s test results – wells that are only a few steps apart may have different water quality.
Besides routine testing, you should also test:
- after major plumbing work or well repairs
- if you detect changes in water quality, including taste, odour, and appearance
- if regular well users experience unexplained health problems that may be water related (e.g. stomach cramps, diarrhoea or vomiting)
- after flooding (if flooding is common in your area you may want to retrofit your well. Contact an MOE licensed well contractor)