Before 1953, lead was used as water service line material for residential houses. Houses built after 1953 used copper. Today, many houses also use PVC plastic for water service lines. All known lead service lines in Markham, from the municipal watermain up to the property line, have been replaced.
All municipalities must test drinking water for lead content. The Ontario Drinking Water Standard for lead is 0.010 milligram per litre. Water with lead content below this concentration Standard is not a health hazard.
As required by Ontario Regulation 170-03, Markham began testing residential water samples in December of 2007. By spring of 2011, after 16 rounds of lead water sampling, over 1400 samples were sampled and tested for lead. These samples were taken on a volunteer basis from many locations throughout Markham – especially older locations.
All lead test results were all well below the Ministry of Environment, Conservation and Parks (MECP) Drinking Water Quality Standards for lead. As a result, the MECP granted Markham regulatory relief from community lead sampling in fall of 2011.
Markham still takes 20 system lead samples each year. There could be private service lines from property lines to houses that are made of lead or contain lead. Also, the internal plumbing of a building may still contain lead pipes. If you think your home might have lead plumbing, please contact a plumber. If you think you might be connected to a lead service line, contact the Contact Centre at 905.477.5530.