But gaps exist in the testing protocols.
Municipal water systems are tested regularly.
Some non-municipal systems are tested by the MOH. Some are tested by the MECP.
And private wells and intakes, which serve about 1.3 million Ontarians, have no mandatory testing requirements.
The City of Hamilton and Durham County, for example, suggest private well owners test their water quality at least three times per year.
But not all residents are following through with their testing, and the water samples confirm that.
Between 2003 and 2022, 35 per cent of water samples from private wells and intakes tested positive for indicators of bacterial contamination, the auditor general’s report says.
And some of that responsibility falls on the MECP too, which oversees the construction, maintenance and decommissioning of wells.
The auditor general’s audit found that the MECP had a backlog of 73,800 well records that still needed to be completed.
The auditor general provided 17 recommendations to support better water testing in non-municipal systems.
The suggestions include creating additional outreach materials about the risks of untreated drinking water, reviewing the definition of unsafe water to ensure the bacteria threshold in private wells protects human health, and develop a plan to clear the MECP’s submitted well records backlog.
The MECP and MOH accepted all the auditor general’s recommendations.