Boil orders

A boil water order is an important health risk management tool available to Regional Medical Officers of Health. The Public Health Act gives officers authority to issue orders requiring certain actions to be taken to address health hazards. When a boil water order is issued, the officer orders the owner of a drinking water system to release a boil water advisory to its customers.

Boiling water will kill any potentially disease-causing microbes, making it safe to drink. Several situations may prompt an order, including:

• unacceptable levels of E. coli or other disease-causing microbes (bacteria, viruses or parasites) at any point in the water distribution system
• unacceptable levels of cloudiness in the water entering the distribution system
• as a precautionary measure if there is a risk of microbial contamination (planned maintenance or unscheduled repairs in the distribution system, equipment malfunction or an environmental emergency)

Last updated: December 5, 2025

For historical data, visit Past boil orders.

During advisories, any water used for cooking, drinking, drink mix preparation, making ice, washing fruits and vegetables or brushing teeth should be boiled.

To kill microbes, water must be brought to a rolling boil for one minute in a heat-resistant container. Once boiled, the water should be left to cool in a safe place, away from children and pets, and then poured into clean, covered containers. Boil water for two minutes when preparing infant formula, regardless of an advisory.

Dispose of all ice cubes, infant formula, mixed drinks and anything made with possibly contaminated tap water before the boil water advisory. Do not thaw frozen food in tap water. All home canning and beer/wine making should be postponed until after the boil advisory has been lifted.

In most situations, it is not necessary to boil water used for household purposes such as bathing, showering, laundry or washing dishes. Adults, adolescents and older children may bathe, shower or wash provided no water is swallowed. Toddlers, infants and immunocompromised individuals should only be sponge bathed during boil water advisories to avoid accidental ingestion.

Hands can continue to be washed using tap water.

Boil water advisories apply to all commercial businesses (restaurants, grocery stores, food processing facilities, dental and medical offices, etc.) and public establishments (hospitals, schools, arenas, pools, community centres, gyms, churches, child care facilities, care homes, etc.) that are connected to the water supply for which the advisory applies. 

During a boil water advisory, commercial businesses and public establishments must follow the conditions below: 

• provide an alternative safe drinking water source (boiled or bottled water) for customers/clients
• post signs at all sinks, drinking fountains and washrooms advising customers/clients and employees not to drink tap water
• disconnect or shut down all beverage dispensers and fountains as well as spray and mist hoses (e.g., grocery store fruit and vegetable sprinkler system) and any other food prep equipment directly connected to tap water lines. This includes all carbonated drink dispensers, iced drink machines, ice cream machines and ice machines 
• dispose of any recently made ice, drinks and uncooked food and disinfect all containers 
• disinfect all dishes, utensils and glassware potentially contaminated prior to the advisory
• do not thaw frozen food in tap water
• all staff must regularly wash their hands
• post signs warning people not to swallow water in public facilities (e.g., gyms, pools and studios). In facilities with an increased risk of shower water being swallowed (e.g., child care and special care establishments), the showers should be shut down
• sanitize dishes by washing them in a commercial dishwasher that has a hot water cycle of 82°C or higher. If dishes are to be washed manually, a sanitizing solution must be used. The dishes must be left to air dry and not rinsed with tap water

After the advisory has been lifted, any pipe or device containing tap water should be cleaned:

• flush out water pipes to ensure the water is safe before using. To do this, turn on cold water at all faucets and run the water until it gets noticeably colder, which can take several minutes. You should begin with the faucet that is highest in your home or building and make your way to the bottom, turning on all faucets.
• run water softeners through a regeneration cycle, following the manufacturer’s directions 
• drain and refill hot water tanks set below 45°C/110°F (normal setting is 60°C/140°F)
• remove and clean all screens and aerators on taps 
• replace water filters in water treatment devices, following the manufacturer’s instructions
• properly flush and sanitize all ice, drink and ice cream machines before reuse