How Often Should You Test Your Well Water?
A well has no treatment plant and no one testing it but you. The schedule Ontario public health recommends, and the events that call for a sample right away.
By Danny Lachhman · Owner, 360WATER Systems Inc. · Orangeville, Ontario
If you’re on a well, there is no municipality testing your water. The testing schedule is yours — and the good news is that the most important test is free in Ontario.
Bacteria (E. coli / total coliform): your local public health unit provides the sample bottles and the lab work at no charge. The standing guidance for private wells is to test for bacteria three times a year — spring, summer, and fall is the usual spread. It’s the single highest-value habit a well owner can have, because bacteria is the one common well problem that can make people sick quickly, and it can’t be seen, tasted, or smelled reliably.
Test right away, whatever the calendar says, after:
- Flooding, or a major melt with water near the wellhead
- Any well work — pump change, well repair, new plumbing
- A change in taste, smell, or colour
- Stomach illness in the house that doesn’t have a better explanation
- The property sitting unused for a long stretch (cottages, after winter)
The chemistry side, every few years: hardness, iron, manganese, pH, TDS, nitrates — the list from our testing post. Chemistry changes slowly compared to bacteria, so this isn’t a three-times-a-year job, but it’s what decides whether your treatment equipment is still matched to your water, and whether a new problem (rising iron, falling pH) is developing.
Keep the results. A single test is a snapshot; a folder of tests over years is a trend, and trends are how you catch a well changing before it becomes a problem. Note the date and season on each one.
One caution that pairs with UV systems: a clear bacteria test is a moment in time, not a guarantee. That’s exactly why UV — disinfection at the tap, every day — exists. Test on schedule, treat continuously, and the two cover each other.
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End of batch 2. Prepared Oct 15, 2026, ahead of the “next week” timing promised when batch 1 shipped, so Danny’s review is the only step left.
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