Drinking Water Systems Regulation

• Regular sampling and testing of water
• Bacteria and chemical testing to be done by accredited laboratories
• Minimum standards for treatment
• Clear requirements for the immediate notification of any adverse water quality
• Public reporting
• Tough penalties for non-compliance
• Mandatory certification of persons who perform operational work in water treatment and distribution facilities, including periodic recertification

Click here to link to the Ministry of Environment for more information about the regulation.

The Provincial Government in Ontario has jurisdiction over water supplies and regulates water quality through the Ministry of the Environment Drinking Water Standards. The standards reflect the most current expertise and procedures in drinking water protection.

The primary purpose of the Ontario Drinking Water Standards is to:

"protect public health through the provision of safe drinking water. Water intended for human consumption shall not contain disease-causing organisms or unsafe concentrations of toxic chemicals or radioactive substances. Water should also be aesthetically acceptable."

Standards for treated water are divided into four categories: two are health related and two are non-health related.

The standards are defined as follows:

 

	MAC: Maximum Acceptable Concentration - Health Related
		This is a health-related Ontario drinking water standard established for contaminants that have known or suspected adverse health effects when above a certain concentration. The length of time the MAC can be exceeded without injury to health will depend on the nature and concentration of the parameter.
	IMAC: Interim Maximum Acceptable Concentration - Health Related
		This is a health-related Ontario drinking water standard established for contaminants when there are insufficient toxicological data to establish a MAC with reasonable certainty, or when it is not practical to establish a MAC at the desired level.
	AO: Aesthetic Objective - Non Health Related
		AOs are established for parameters which may impair the taste, smell or colour of water or which may interfere with good water quality control practices.
	OG: Operational Guidelines - Non Health Related
		OGs are established for parameters which need to be controlled to ensure efficient treatment and distribution of the water.