- Where does my drinking water come from?
- How is Ontario’s drinking water treated?
- I want to learn more about Ontario’s drinking water. What can government reports tell me about my drinking water?
- If my drinking water is safe, why are water advisories sometimes issued?
- A boil water/drinking water advisory has been issued to my community. What should I do?
- How good is Ontario’s drinking water?
- Why should I choose tap water?
Where does my drinking water come from?
Ontario’s drinking water comes from surface water or groundwater.
Surface water is taken from rivers, lakes and reservoirs. The Great Lakes contain 95 per cent of North America’s supply of fresh water and one-fifth of the world’s supply of fresh surface water. More than 70 per cent of Ontarians get their drinking water from the Great Lakes.
Groundwater is found under the earth’s surface. Aquifers, the spaces between layers of sand, gravel and rock, store water flowing down from the surface. Groundwater supplies wells all over Ontario.
You can pinpoint the lake, river or well that supplies the drinking water treatment facility in your community by viewing “where does my water come from?”
How is Ontario’s drinking water treated?
If your drinking water comes from your municipality, in most cases, this is what happens in a municipal water treatment plant.
Step 1 – Water is taken from a river, a lake or a well.
Step 2 – Chemicals added to the water cause particles to clump together into larger particles. These larger particles fall to the bottom and are later removed.
Step 3 – Smaller particles are taken out through filtration by passing the water through a bed of sand, gravel, charcoal or a membrane.
Step 4 – The water is disinfected with chlorine. A small amount of chlorine stays in the water as it makes its way to your tap, in order to ensure the water continues to be protected.
To find out what treatment processes are used by the drinking water system in your community, look for your municipality on the drinking water quality map.
I want to learn more about Ontario’s drinking water. What can government reports tell me about my drinking water?
Check out the Minister’s annual report on drinking water, which provides the public with an overview of Ontario’s activities to protect drinking water.
Review the Chief Drinking Water Inspector’s annual report, which focuses on drinking water quality and inspection results for drinking water systems and laboratories licensed to perform drinking water testing.
In 2009-10, almost all (99.88 per cent) of water quality tests from municipal water systems met Ontario’s rigorous drinking water standards.
You can view all drinking water reports in our resources library.
If my drinking water is safe, why are water advisories sometimes issued?
Ontario’s safety net for drinking water protection ensures reliable drinking water is delivered to your community. Ontarians can have confidence that the drinking water delivered to their homes is safe, and that appropriate actions are swiftly taken in situations where there are adverse conditions.
Drinking water advisory notices are used to protect the public when the safety of drinking water may be in question and as a precautionary measure during times of system maintenance.
Advisories remain in place until corrective actions have been taken and the health unit is satisfied water is safe.
In most cases, system owners are able to fix the issue quickly.
Sometimes designing and installing new treatment devices is required to resolve the issue and the advisory may remain in effect for longer periods of time.
A boil water/drinking water advisory has been issued to my community. What should I do?
The extent of restriction on water use depends on the situation and the reason for issuing a boil water advisory. Always follow your own public health unit’s recommendations on water use.
For more information, see How to use water safely during a “boil water advisory" on the Ministry of Health and Long-Term Care’s website.
How good is Ontario’s drinking water?
Ontario’s drinking water is among the best protected in the world and we are working hard to keep it that way.
Tests conducted on samples from Ontario’s drinking water systems consistently show that almost all municipal residential drinking water systems are meeting Ontario’s rigorous health-based standards.
Ontario has a world-class system – a safety net – to protect drinking water from its source to your tap.
Why should I choose tap water?
By choosing to use Ontario’s tap water, you are making a positive difference in the environment and saving money.
Tap water is the most inexpensive drinking water choice, costing about 1/8th of one cent per litre.
Drinking tap water tastes good and is environmentally friendly. It is also economical and good for our health.
