Water is delivered to Markham through City of Toronto watermains. Toronto has some old neighbourhoods with old water services that contain lead. The water in this service line can absorb some of this lead. In Markham, we do not have lead services and do not have this problem. We know this because we conducted thorough testing in homes and did not find elevated levels of lead.
To fix its problem, Toronto is taking steps to control corrosion. It's corrosion control plan (CCP) includes phosphate dosing. Phosphates coat the pipes, prevent corrosion, and reduce the amount of lead in drinking water.
The use of phosphates will increase in the total phosphorous found in Markham's tap water up to 1 mg/L. Phosphorous is naturally present in food (such as milk, nuts, and beef) and will have No Impact on drinking water quality. Most users won't notice a change to their water.
If you are an Industrial, Commercial, and Institutional (ICI) water user, you may be slightly affected. If you use municipal water for commercial heating or cooling, manufacturing, or other uses, please contact your heating or cooling supplier or process consultant. They will tell you whether you need to make minor adjustments.