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Boil Water Advisories

A Boil Water Advisory (BWA) is issued by Halton Region’s Medical Officer of Health when bacteria or other microorganisms may be present in the municipal drinking water supply, making it unsafe to drink. During a BWA, residents are advised to boil their water before using it for drinking, washing or preparing food, and brushing teeth.
This page includes information about BWAs and guidance on how to use water safely during this type of advisory.

Frequently Asked Questions

A BWA is a public notice issued by the Medical Officer of Health to protect public health. Residents are advised to boil their water before consuming it to prevent illness from disease-causing microorganisms that may be present in the municipal water supply.

A BWA remains in place until laboratory testing confirms the safety of the water supply, and the Medical Officer of Health lifts the advisory.

A BWA may be issued for a number of reasons, such as:

  • test results indicate the presence of bacteria in the water supply; or
  • there is a risk of bacterial contamination due to a watermain break or a mechanical problem.

Halton Region may communicate a BWA in the following ways:

  • Letter to homes/businesses
  • Media release to alert local news outlets
  • Automated phone call
  • Social media (Twitter, Facebook, Instagram)
  • 311 call centre

Bring the tap water to a rolling boil for at least ONE MINUTE before using it to:

  • drink
  • prepare food, including ice and hot/cold drinks
  • make infant formula or food for baby
  • wash fruits, vegetables and other food
  • brush teeth, gargle and rinse dentures

Boiled water can be cooled, stored in a clean and sanitized food container with a lid, and refrigerated.

Yes. Commercially bottled water or water from a public drinking water supply that is not affected by the advisory can be used.

  • Adults, teens and older children may shower or bathe using tap water, but should avoid swallowing the water. Babies and young children can be given sponge baths instead of tub baths or showers.
  • Use boiled (and cooled) or bottled water for handwashing. Alcohol-based (60-90 per cent alcohol) hand rub can be used when hands are not visibly dirty.
  • Dishwashers that use hot water (final rinse temperature of at least 65ºC) or have a sanitizing cycle will disinfect dishes.
  • Use boiled or bottled water to wash and rinse dishes by hand. Or, use tap water to wash and rinse dishes, then soak them in a bleach and water solution for at least one minute and let them air dry. A bleach and water solution can be made by mixing 30 mL of liquid household bleach in 13.5 litres of lukewarm water.

No, laundry can be done as usual.

Yes. Household water filters, such as activated carbon filters, typically do not remove bacteria or viruses.

No. The water is not safe to use in wading pools or for water play because children may swallow it.

Before drinking the water:

  • run cold water faucets for one minute or until the water feels cold.
  • run water softeners through a regeneration cycle.
  • drain and refill hot water heaters set below 45°C (113°F). Normal setting is 60°C.
  • replace water filters and follow manufacturer’s instructions for cleaning and sanitizing appliances with water line connections.