There are different reasons for issuing a boil water advisory. A boil water advisory can be based on bacteriological (microbial) examination, including the finding of bacteria or parasites. A boil water advisory can be based on information indicating that the water is not safe to drink, for example, the absence of disinfection residual in the drinking water. (Disinfection is a cleaning process that destroys most disease-causing micro-organisms.) As well, a boil water advisory can follow the occurrence of an outbreak of illness in the community that has been linked to consumption of the water. Always follow the health unit's recommendations on water use.
The extent of restriction on water use depends on the situation and the reason for issuing a boil water advisory.
How to 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 a rapid rolling boil and boiled for 1 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. Throw out all ice and disinfect the ice cube trays. Make ice using boiled, cooled water.
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.
Handwashing
Depending on whether the BWA is precautionary or is the result of a known disease outbreak, use one of the following statements:
The boil water advisory has been issued as a precaution, and there is no known outbreak of human illness. The water can be used for handwashing without additional hand disinfection with bleach solution or alcohol.
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 imperial gallons (45 litres) water. A smaller quantity may be produced by adding 5 ml (about one teaspoon) of liquid household bleach to 4.5 litres (1 imperial gallon) of water. Mix and let stand for at least 10 minutes prior to use.
Other ways of disinfecting hands
You can use alcohol-based hand 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. Please refer to information on "Hand Hygiene". The wet wipes used for cleaning babies at diaper change are not effective for disinfecting hands and should not be used for this purpose.
Disinfecting toys
Toys should be cleaned and disinfected if your child has diarrhea. 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) liquid household bleach to 1 imperial gallon (4.5 litres) of water). Dip toys into this solution and air-dry them. Cloth and plush toys could be washed or dry-cleaned.
Using the dishwasher
If the dishwasher has a hot or sanitize setting (where water reaches at least 82°C / 180°F for at least 10 seconds), it safely disinfects dishes. If your dishwasher does not have such a setting, after finishing the cycle, soak dishes for 1 minute in a solution of 1oz (30 ml) of liquid household bleach mixed with 3 imperial gallons of lukewarm water (13.5 litres). Let dishes air dry.
Wash dishes by hand
You could use water that has been boiled for washing dishes. Dishes washed in soap and hot water can also be rinsed in water that has been boiled or disinfected with the following bleach solution. Mix 1 oz. (about 30 ml) liquid household bleach in to 3 gallons (13.5 litres) of water. Let dishes soak in the solution at room temperature for at least 1 minute. Let dishes air dry.
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 strong bleach solution. Mix 1/4 cup (about 60 ml) bleach in 1 imperial gallon (4.5 litres) water for this purpose. Do not reuse or store this solution, but make it fresh daily. Smaller quantities may be made, by adding 15ml (about 3 teaspoons) of household bleach to 1 litre of water. Use half the amount of liquid household bleach (30 ml) if there has been no contact with raw meat.
Doing laundry
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.
Wading pools
The water is not safe to use in wading pools. Water usually gets into the mouths of small children, providing a possibility for infection.
Water filtration devices
Filtered water does not necessarily make the water safe for drinking or cooking. Filtered water should also be brought to a rolling boil for 1 minute before drinking or using it for cooking.
Immunocompromised persons
Immunocompromised persons should always follow their 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.
Lifting a boil water advisory
The Ontario Drinking Water Standards state that the medical officer of health should continue the boil water advisory until two consecutive sets of samples are taken from all parts of the water system which has been affected and show that the water is safe for drinking. The ODWS address 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.
What to do when the boil water advisory is lifted
Run cold water faucets for 1 minute before using the water. Run drinking fountains for 1 minute before using the water. Flush all garden hoses by running cold water through them for 1 minute. Run water softeners through a regeneration cycle. Drain and refill hot water heaters set below 45°C (normal setting is 60°C).