The Ontario drinking water quality standard for lead is 10 micrograms per litre. This standard is based on a national guideline set by Health Canada.

What happens if a child care centre or school finds it has lead in its drinking water above the standard for lead?
If a child care centre or school gets a drinking water test result that is above the standard for lead, the local Medical Officer of Health will assign corrective actions to the facility and it is the facility’s responsibility to ensure those actions are carried out. The Ministry of the Environment and Climate Change will follow up with the facility operator and local Medical Officer of Health if necessary. These local processes have been in place since 2007 and are working well.