Although, children and pregnant women are at risk for the most negative side-effects from lead, everyone should keep in mind it's poisonous. (CBC)

By their very nature, the pipes a plumber might work on in your house tend to be made of lead.

After all, the Latin word for lead is plumbum.

For so many post-war suburban homes, pipes that carry water indoors contain this poisonous metal.

Lead systems also funnel drinking water into most Victorian-era homes, common in cities and towns across Canada, like Ottawa and Montreal.

The City of Ottawa estimates about 28,000 homes built before 1955 have lead pipes.

But pipes in newer subdivisions aren't made with lead. And some homes that have had construction done nearby may have had safer copper replacements installed by the city.

This week, the Province of Ontario ordered 36 municipalities to undergo testing after higher-than-normal levels were found in water in homes in London.

Preliminary water tests at Queen's Park also came back abnormal. Seven of 20 tested sources of tap water at the Ontario legislature were found to have higher-than-allowable levels of lead.

'It's dangerous to anyone'

According to many experts, no level of lead is safe.

"Sometimes you hear politicians talking about safe levels and unsafe levels," said Gideon Forman, executive director of the Canadian Association of Physicians for the Environment (CAPE). "Well, there's no such thing as a safe level of lead, because any amount can make you sick."

Although, children and pregnant women are at risk for the most negative side-effects from lead, everyone should keep in mind it's poisonous.

In fact, male infertility has been connected to higher lead levels in water, paint and fossil fuel emissions.

It is usually associated with more than one source of lead exposure, not just water. For example, a man living in an older home with lead paint and pipes is at higher risk.

For exposure, paint has to be chipping, and is often transmitted to people through dust.

With the switch to unleaded fuel, lead in gasoline is not as much of a concern anymore. But emissions from manufacturing plants and mining can be a problem, especially for nearby homes.

Studies have shown lead damages nerve connections, causing brain and blood deficiencies.

"It's dangerous to anyone. But our major concern is around the developing brain and nervous system for children," said Forman. "Children who are exposed to lead can suffer from learning disabilities, behavioural problems, and IQ can be affected."

Ontario is now requiring schools and day cares built before 1990 to test for lead in tap water annually.

Also a problem in Montreal

Two years ago, water tests conducted with some Montreal wartime houses, built between 1940 and 1950, revealed lead contents slightly exceeding the new Quebec standard.

Then in March, the city warned residents that water sources to certain homes built in the 1960s could also be contaminated.

The homes possibly affected were ones with less than eight units. Some of these were connected to the municipal waterworks system's lead pipes. Water that stagnates in these pipes could cause the lead to dissolve into the water.

The health and safety of residents is the most important issue here," said Sammy Forcillo, executive member of the infrastructures, roads and water committee. "To remedy the situation permanently, the city will replace the lead connecting pipes at the same time it will replace the lateral mains."

Halifax tests regularly for lead

Since 2000, Halifax has been testing regularly for lead in drinking water across the city.

A sample of 20 homes represents the city geographically, and takes into consideration different types of plumbing systems. The study also tests homes of varying ages.

Samples are taken after water has been sitting in the system, which tends to show higher lead levels.

The study found one of the homes with lead pipes tested slightly higher than the others. But it didn't exceed Canadian lead regulations, according to Reid Campbell, Halifax regional water commission plant operations manager.

The City of Halifax will split the cost of replacing lead pipes with residents. If they don't want to pay, Campbell's team recommends running the water for two minutes before drinking it. In Ontario, the recommendation is five minutes.

"The lead's not coming from the water. The water's absorbing it from the [pipe] service, the solder or brass," explained Campbell.

Ottawa offers a similar replacement initiative as part of a pilot program. The city will replace lead pipes, including the portion on private property that is the homeowner's responsibility, and share the cost with the homeowner. Homeowners are also offered five- and 10-year financing plans to help cover the $2,000 to $3,000 cost.

Mineral buildup cancels out lead

About 15 years ago, the City of Regina found lead concentrations in the water systems of older homes. But the minerals specific to the city's water supply cancelled out possible exposure risks.

"We have a buildup of minerals inside our pipes, so the water isn't actually in direct contact with the lead," explained Ken Wiens, Regina engineering and works department water engineering manager. "There's a film on the inside of the piping. That's our water chemistry, and our water source causes that."

But in other regions, because lead is as common as plumbers, it's best for homeowners to check for themselves, by looking at the pipes between the basement floor and water meter. When scratched with sandpaper, a pipe with lead remains grey. One with copper turns reddish.