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Environmental Health & Prevention Services
PDF of Fact Sheet - Lead in Drinking Water (May, 2008)
Lead is a toxic metal that was used for many years in products found in and around homes. Lead is also present almost everywhere in nature. It can be found in the air, soil, dust, drinking water, food, and in consumer products.
Concentrations of lead in the environment increased significantly following the industrial revolution, however, over the past 25 years regulatory agencies have substantially reduced Canadian’s exposure to lead. The Guidelines for the Canadian Drinking Water Quality specifies that the lead level in drinking water must be below 10 micrograms per litre (ug/L) after flushing.
Typically, lead gets into your water after it leaves your local water treatment plant or your well. Levels of lead in drinking water can result from the use of lead solder in plumbing, lead service connections that link the house to the main water supply, lead pipes in the home or from brass fixtures. Older homes, particularly those constructed before 1955, often contain lead water service lines. In newer homes, excessive leaching from leaded solder and brass fixtures (e.g. faucets), may occur for the first year until a protective oxide layer has formed in the pipes.
For lengthy periods of time (over 6 hours), lead can dissolve into drinking water that is left standing in household piping made with these materials. The most common cause is corrosion, a reaction between the water and the lead pipes or solder. Dissolved oxygen, low pH (acidity) and low mineral content in water are common causes of corrosion. All kinds of water, however, may have high levels of lead.
There have been very few reported cases of lead poisoning in Canada. The health effects of lead are most severe for infants and children under six years of age, pregnant women and nursing mothers. Because of the smaller mass and higher metabolism of children under six years of age, exposure to high levels of lead in drinking water can result in delays in physical or mental development. Lead from water may account for up to 10% of the lead blood level in children, recognizing the major sources of lead are still non-water related. For adults, high lead levels can result in kidney problems or high blood pressure.
The Ontario Drinking Water Quality Standard for lead is 10 micrograms per litre (ug/L). This standard is based on a prudent (more protective) estimate that takes into consideration the health of young children and pregnant women, who are the most vulnerable to the health effects of exposure to lead.
If your water has been shown to have lead levels below the standard of 10 micrograms per litre, it is recommended that you run your water for at least five minutes after an extended period of non-use. Filtration systems or bottled water are not needed in this type of scenario.
If your water has been shown to have lead levels above the standard of 10 micrograms per litre, then the following recommendations should be followed:
1. What should households with children under 6 years of age and pregnant women do?
Even though drinking water normally contributes only a small percentage of total lead intake, lead exposure should be reduced whenever possible, especially in young children and fetuses. Please follow these recommendations.
Children under the age of 6 and pregnant women should drink bottled water or use an approved filter attached directly to the tap or systems installed in the plumbing systems. Make sure any filtration product purchased is certified and check the National Sanitation Foundation (NSF) website at www.nsf.org/certified/dwtu to ensure that the filter is effective in reducing lead levels.
This recommendation is particularly important for infants whose formula is prepared by adding tap water to liquid concentrate or powder.
When using filtration devices it is important to follow the manufacturer’s instructions carefully. When using a filter that is directly attached to the tap, ensure that the water is flushed for at least 30 seconds.
The label on bottled water should be checked to ensure it is lead-free. Lead content is listed on the “Analysis Label” and is also referred to as “Pb”. The water is lead-free if the value for lead is zero. It is important to note that not all bottled water is lead-free.
If your water has been tested and shown to have lead levels below the recommended 10 micrograms per litre, continue to flush your water for at least 5 minutes before use. Filters and bottled waters are not needed.
Children less than 6 years of age: Younger children are still developing and are more sensitive to the neurological and blood effects of lead. As well, children less than 6 years of age absorb lead more easily than adults. Particular recommendations are made for formula-fed infants because the water used to make the formula can contribute 40-60% of an infant’s lead intake, whereas drinking water in older children and adults only contributes approximately 10% of total lead intake.
Pregnant women: Pregnant women can pass lead in their blood to their fetus during pregnancy. Therefore, particular recommendations are made to keep lead levels in pregnant women as low as possible.
2. What should households with older children and non-pregnant women do?
Run the water from the drinking water tap if it has been sitting in the pipes for 6 hours or more. Water should be flushed for at least five minutes. (More information on how to run or flush your water is listed below)
Use cold, flushed water for drinking and preparing food. Water from the hot water tap should not be consumed as heated water generally contains higher lead levels.
3. Do breastfeeding mothers need to use filtered water or bottled water?
No. The amount of lead found in the breast milk of women who drink tap water in homes served by lead service lines does not constitute a risk to their infants' health. Breastfeeding mothers should follow the recommendations for non-pregnant women.
4. Do older children and non-pregnant women need to use filtered water or bottled water?
Generally, no. Older children and non-pregnant women usually get only a small percentage of their lead from water. Most lead exposure comes from food. Also, young children can be exposed to lead from eating dirt and dust from the environment.
Standards for lead in water have been lowered significantly over the years. Levels slightly over the acceptable levels of 10 micrograms per litre are very unlikely to cause health effects for older children and non-pregnant women.
5. What if my child has been drinking water from the tap? Should I be concerned?
No. Over the years, the major sources of lead exposure for children have decreased significantly because of the elimination of lead in gasoline, paint and solder in tin cans. Other jurisdictions have similar lead issues in their drinking water systems. In some areas where lead toxicity is reportable to public health, significantly elevated lead levels in blood have not been reported. Parents are advised to discuss specific health concerns with their physicians.
6. Can I use the water for bathing, showering, and washing dishes and clothes?
Yes. Activities such as bathing, showering and washing dishes and clothes do not expose people in the house to lead.
People with lead service lines or who have had lead detected in their water through testing, should "run" or "flush" their water lines when the water has been sitting in the pipes for longer than 6 hours as follows:
When water has been sitting in the pipes for 6 hours or more:
Let the water run from the cold drinking water tap at medium flow for 5 minutes.
- OR -
Take a shower or run a major appliance such as a washing machine or dishwasher and then let the water from the cold drinking water tap run for 2 minutes at medium flow before using for drinking or food preparation.
To avoid having to run your water each time it has been sitting in the pipes for 6 hours or more, you can run your water as described above and then fill kettles, pitchers and pots with enough flushed water for drinking and food preparation during the day.
Except in formula-fed infants, drinking water normally contributes only a small percentage of total lead-intake. Lead in other sources has been significantly reduced by the elimination of lead in gasoline, paint and solder in tin cans. In older houses, lead-based paints may remain a source of lead exposure, particularly to children who may eat lead-based paint chips or dust. Measures to reduce lead exposure in the home can be found online at:
No. The City of Sarnia water has very low levels of lead – typically less than 1 microgram per litre. This is significantly lower than the Ontario Drinking Water Quality Standard of 10 micrograms per litre. Concerns have only been raised with regard to lead service lines in homes built before 1952.
For further information on the health effects of lead, please contact the Community Health Services Department at 519 383-8331 ext. 3576.
You can find more information on lead from the following links.
Canada Mortgage and Housing Corporation: