May 20,



Lead is a toxic material that is harmful to human health if inhaled or ingested.  The human body cannot tell the difference between lead and calcium, which is a mineral that strengthens the bones.  Like calcium, lead remains in the bloodstream and body organs such as muscle or brain for a few months.  Lead that is not excreted is absorbed into the bones, where it can collect for a lifetime.

Young children (under the age of 6), infants and fetuses appear to be particularly vulnerable to lead poisoning.  Growing children will more rapidly absorb any lead they consume.  A child’s mental and physical development can be irreversibly stunted by over-exposure to lead.

Although the issue of lead in drinking water surfaced in London, Ontario a few weeks ago, health concerns with lead in drinking water is not a new issue.  Typically lead gets into drinking water after the water leaves the water treatment plant.  The primary source of lead in drinking water comes from the service piping and the private plumbing system, including lead pipes, lead solder on copper pipes, and lead in brass fittings.

Local Lead Testing

All known municipal lead services (up to the property line) in the city of Peterborough have been replaced with copper.  The use of lead solder in plumbing was discontinued in 1993.  The Peterborough Utility Services adds a corrosion inhibitor to Peterborough’s drinking water which minimizes the reaction between the water and any lead pipes or solder.

The Maximum Acceptable Concentration (MAC) for lead in drinking water is 10µg/L.

There are 4 additional large municipal residential water systems in Peterborough County aside from the City of Peterborough’s system.  Below are the most recent lead results for these systems:

Millbrook – tested on Jan15, 2007  Result: 0.56 ug/L (acceptable)

Norwood – tested on March 19, 2007 Result: 0.3 ug/L (acceptable)

Lakefield – tested on August 8, 2006  Result: 0.27 ug/L (acceptable)

Havelock – tested on March 12, 2007 Result: 2.38 ug/L (acceptable)

Additional sampling was completed in Peterborough to test the lead levels at the tap in 30 homes.  This testing would reveal if the home plumbing was contributing lead to the water.  Only one sample was found to be higher than the drinking water standard, and the lead piping at that site has already been replaced.

Residential Lead Plumbing

Homes with lead plumbing could still see elevated levels of lead in their drinking water, especially in standing water samples.  Lead piping was occasionally used in “wartime” houses, which were constructed in the years 1942 to 1947.  There was also some use of lead from 1898 to 1907.

Homeowners can check to see if they have lead pipes by examining their plumbing lines, especially at the main shut-off valve.  Copper pipe will be orange or brownish in colour.  Galvanised or iron pipe will appear blackish, may show threading at connections which are screwed together, and will stick to a magnet.

Lead pipe will also have a very dark colour.  Homeowners should clean a section of pipe off with a cloth, and then rub a white piece of paper on the pipe.  If it looks like a pencil has been rubbed on the pipe, it is most likely lead.

Removing lead piping from plumbing systems is the best way to resolve lead concerns in the home.  This work is the responsibility of the homeowner and should be performed by a licensed plumber.


Peterborough Public Health provides the following recommendations to homeowners concerned with lead in drinking water:

  • Do not drink water that has been standing in your household water pipes for more than six hours.  Let the water run for a few minutes or until it feels cold to the touch.  Heavy water use such as showering or toilet flushing will also flush standing water from your pipes.
  • Always use cold, fresh water for drinking, cooking, making baby formula and preparing beverages.  Hot water is likely to contain higher levels of lead.
  • Have your water tested for lead by a accredited laboratory.

Last modified on Feb 10, 2017