Toronto’s tap water is safe to drink. It’s clean, affordable and environmentally friendly.
The City provides clean, safe drinking water to residents, businesses and visitors. This is done through a complex water treatment process and continuous testing to make sure water always meets or exceeds the requirements of the Safe Drinking Water Act set by the Ministry of the Environment, Conservation and Parks (MECP).
Why Choose Tap Water
Safe and high quality
Toronto’s drinking water comes from Lake Ontario, a high-quality source. The City treats the water to meet or exceed MECP requirements, which are among the world’s strictest drinking water standards.
Costs less than bottled water
Filling up a standard reusable water bottle costs less than one cent, while bottled water can cost as much as 200 times more.
Better for the environment
Choosing tap water over bottled water helps reduce plastic waste and supports lower greenhouse gas emissions.
Tap Water Testing
The City continuously tests, monitors and analyzes its drinking water to make sure it meets the strict standards set by Toronto Public Health, the Province of Ontario and the Government of Canada.
The City’s accredited and licensed lab:
tests drinking water samples from the water treatment plants every six hours for bacteriological quality (almost 6,000 times a year)
conducts more than 20,000 tests at the water treatment plants every year
conducts more than 15,000 tests on samples collected from the water distribution system ever year
You can review the latest drinking water quality and system reports submitted to the MECP on the operations, capital and operating budgets of the drinking water system.
Drinking Water Treatment & Supply
Each day, the City treats more than one billion litres of safe drinking water at four water treatment plants. These plants operate 24 hours a day, seven days a week.
How water is treated
Water is collected from Lake Ontario through intake pipes located between one and five kilometres away from shore, deep below the lake surface.
Lake water passes through screens to remove large debris. The water is then disinfected with chlorine or ozone.
A coagulant chemical is added to the water to bring particles in the water together and form larger particles called floc.
At some water treatment plants, the water travels through settling basins where larger particles settle to the bottom and the clear water proceeds to the next treatment step.
The water then passes through filters containing sand and anthracite (also known as hard coal) or activated carbon to remove impurities and microorganisms.
Before water is distributed to homes and businesses, the City adds:
chlorine to destroy bacteria and viruses
fluoride to help prevent tooth decay
ammonia to maintain chlorine levels as water travels through the distribution system
To ensure an uninterrupted water supply, a computerized process control system automates equipment operations. The system enables City staff to make timely adjustments and supports cost-effective operations.
Toronto’s water distribution system is divided into six pressure zones and subdivided into 13 pressure districts. This allows City staff to monitor and adjust the system to meet changing demand while maintaining adequate water pressure and supply for customers. The City also stores additional water in tanks and reservoirs to help maintain water pressure and a reliable supply during peak periods and emergencies, such as fires, watermain breaks and power outages.
Commonly Asked Questions About Tap Water
Cloudy water
Cloudy water is usually safe to drink and use. The cloudiness is often caused by air bubbles in the water that should disappear within a few minutes. Air bubbles in the water can occur when:
different temperatures of water enter the plumbing system
the water service has been temporarily turned off during construction
there are valve changes in the distribution system (a valve is a device that regulates, directs and controls the flow of safe drinking water in watermains)
To reduce the cloudy appearance:
run a cold water tap for a few minutes to allow the air to escape
pour some cold water into a glass and let it sit. The air bubbles should rise to the surface and clear up within a few minutes. If the water is still cloudy or contains sediment, submit a water quality service requestor contact 311.
Chlorine
Chlorine is used in the drinking water treatment process to control bacteria, algae and viruses. It also helps protect the water from contamination as it travels through the distribution system and ensures the water remains safe to drink when it reaches customers.
The City monitors chlorine levels at the treatment plants and at strategic locations in the distribution system to ensure the water is safe to drink. The range of chlorine used is set by the MECP.
If you’re sensitive to the taste or smell of chlorine, fill a pitcher with water and leave it in the refrigerator overnight to let the chlorine dissipate. You can also add ice and a slice of lemon, lime or other fruit to the water.
Fluoride
Fluoride is added to Toronto’s drinking water to reduce the risk of tooth decay.
Fluoride levels in Toronto’s drinking water are regulated under Ontario’s Safe Drinking Water Act administered by the MECP.
Discoloured or rusty tap water can happen for different reasons.
If only one tap is affected, the issue is likely within your home’s plumbing. You may wish to contact a plumber.
If all taps are affected, possible causes include plumbing work on your property, nearby construction on a watermain or nearby fire hydrant use. Get tips on how to resolve discoloured tap water.
Earthy or musty smell or taste
An earthy or musty smell or taste can occur in late summer or early fall and can be caused by naturally occurring algae and high water temperatures in Lake Ontario.
The water remains safe to drink during these events.
If you’re sensitive to the smell or taste, you can fill a pitcher with water and let it stand overnight in the refrigerator or add ice and a slice of lemon, lime or other fruit to your water.
Microplastics are tiny plastic particles under five millimetres (mm) in size and enter the environment through human use.
There is currently no standard method for sampling and measuring microplastics in drinking water. This makes it difficult to compare studies or reliably predict potential exposure, effects, hazards or risks.
The MECP does not currently require sampling or testing drinking water for microplastics.
The City’s water treatment plants use a multi-barrier treatment system which can remove small particles, including microplastics in the one to two micron size range (one micron is equal to 0.001 mm).
The specific treatment step that removes the microplastics is referred to as chemically assisted filtration. This involves adding a coagulant chemical, followed by rapid mixing (coagulation), gentle mixing (flocculation) and granular media filtration. This process removes solids in the water by passing it through a bed of granular material, such as sand and carbon.
Water hardness refers to the amount of dissolved calcium and magnesium in water.
Toronto’s drinking water comes from Lake Ontario and contains relatively low levels of these minerals. This means that water hardness is not a concern for most homeowners and water softening systems are usually not needed.
If mineral deposits build up on fixtures, you can remove them with vinegar or a commercial hardness remover.
Lead and drinking water
The water that leaves the City’s water treatment plants does not contain lead.
Lead is most often found in homes built before the mid-1950s when residential water service pipes were commonly made of lead. Lead can also be found in solder used to join pipes before 1990, leaded-brass fixtures like faucets and valves and in-home plumbing in older homes.
