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What are the reasons for a "boil water advisory"?

A boil water advisory is generally based on bacteriological (microbial) examination of drinking water, including the finding of bacteria or parasites.

A boil water advisory may also be based on information other than bacteriological examination indicating that the water is not safe to drink (e.g., the lack or absence of disinfection residual in the drinking water).

A boil water advisory may follow the occurrence of an outbreak of illness in the community that has been linked to consumption of the water.

The extent of restriction on water use depends on the situation and the reason for issuing a boil water advisory.  Always follow the health unit’s recommendations on water use.

General recommendations on how to use the water if a boil water advisory has been issued in your community.

How do I use water when a boil water advisory has been issued?

The water should not be used for drinking, making infant formula and juices, cooking, making ice, washing fruits, vegetables or brushing teeth.  For these purposes, boiled water or bottled water should be used.  The water should be brought to rapid rolling boil and boiled for at least 1 (one) minute.  If there are children in the home, place the pot on the back burner to avoid scalds.  Boil only as much water in a pot as you can comfortably lift without spilling.  Discard all ice made previously and disinfect the ice cube trays.  Make ice using boiled, cooled water.

Can I take a bath?

Adults and teens may shower with untreated water as long as no water is swallowed. Older children could also be given a shower with a hand held showerhead, avoiding the face. Younger children should be sponge-bathed instead of bathing in a tub because they are likely to swallow tub water.

Can I use the water for handwashing?

If the boil water advisory has been issued as a precaution and there is no outbreak of human illness, there is no need for additional hand disinfection with bleach solution or alcohol using the measures described below. If the boil water advisory has been issued because of an outbreak, water can be used for handwashing after the following emergency water treatment: Place 1.5 oz. (about 45 ml) liquid household bleach in 10 gallons (45 litres) of water. Mix and let stand for at least 10 minutes prior to use.

How else can I disinfect my hands?

You can use alcohol-based disinfectants, containing more than 60% alcohol. These products are widely used in the health care setting after washing hands or in situations when water is not available. The wet wipes used for cleaning babies at diaper change are not effective for disinfecting hands and should not be used for this purpose.

My child was ill with diarrhea. Should I clean/disinfect toys?

Yes, toys should be cleaned and disinfected. If the toys are visibly soiled, wash them first with soap and water and then disinfect with a freshly prepared bleach solution (1/4 cup [about 60 ml] bleach in to 1 gallon [4.5 litres] of water). Dip toys in to this solution and air-dry them. Cloth and plush toys could be washed or dry-cleaned.

I have a dishwasher. Is it safe to use?

If your dishwasher has a hot setting, it safely disinfects dishes. If your dishwasher does not have a hot setting, after finishing the cycle, soak dishes for 1 minute in a solution of 1 oz. (30 ml) of bleach mixed with 3 gallons of lukewarm water (13.5 litres). Let dishes air dry.

I wash dishes by hand. How do I disinfect them?

You could use boiled water for disinfecting dishes or with a bleach solution.  Mix 1 oz. (about 30 ml) bleach in to 3 gallons (13.5 litres) of water at room temperature for at least 1 minute.  Let dishes air dry.

What is disinfection?

Disinfection is a cleaning process that destroys most disease causing microorganisms (pathogens).

How do I disinfect countertops, chopping boards or utensils that have come into contact with raw meat?

Countertops, chopping boards or utensils which have come into contact with raw meat should be washed with soap and hot water first, then disinfected with a bleach solution stronger than that used for emergency hand disinfection,  Mix ¼ cup (about 60 ml) bleach in to 1 gallon (4.5 litres) water for this purpose.  Do not reuse or store this solution, but make it fresh daily.

Should I change the way I am doing laundry?

No, continue doing laundry the way you usually do.  If you have to launder sheets heavily soiled with feces, carefully remove soil before you place the sheets into the washer, without much agitation of the cloth.  Use rubber gloves when handling heavily soiled sheets.

Is the water safe to fill wading pools for children?

No, the water is not safe to use in wading pools.  Water usually gets into the mouths of small children, providing a possibility for infection.

I have a water filtration device installed.  Does this make the water safe for drinking or using it for cooking?

No.  Filtered water should also be brought to a rolling boil for 1 minute before drinking or using it for cooking.

My doctor told me I am immunocompromised.  What should I do?

Always follow your physician’s and dietitian’s advice.  You might be advised to use bottled water or to boil water for drinking/cooking, even in the absence of a boil water advisory.

How does the Medical Officer of Health decide when to "lift" a boil water advisory?

The Ontario Drinking-Water Quality Standards (ODWQS) state that the Medical Officer of Health should continue the boil water advisory until the objectives in the ODWQS are no longer exceeded in 2 (two) consecutive sets of samples taken from all parts of the distribution system that has been affected.  The standard addresses the issues that can affect health such as the presence of E. coli.  The Medical Officer of Health may choose not to lift the boil water advisory even if two acceptable samples are obtained.  The Medical Officer of Health may also require the water works owner provide the Health Department with written confirmation from the Environmental Assessment and Approvals Branch, Ministry of Environment, stating that the water system is in compliance with the minimum treatment requirements according to O. Reg. 170/03 Drinking Water Systems.

What should I do after the boil water advisory is lifted?

  • Run cold water faucets for 1 (one) minute before using the water.
  • Run drinking fountains for 1 (one) minute before using the water.
  • Flush all garden hoses by running cold water through them for 1 (one) minute.
  • Run water softeners through a regeneration cycle.
  • Drain and refill hot water heaters set below 45°C (normal setting is 60°C).

More information can be obtained from Durham Region Health Department, Environmental Help Line, 905-723-3818 or 1-888-777-9613.

April 22, 2013

For more information call
905-668-7711 OR 1-800-841-2729