From the Ice Age to the Second Millennium
Canada has about 7 per cent of the world's total renewable freshwater supply. It may seem that water in Canada is abundant, but many parts of the country have experienced water shortages.

Only a small portion of the water in lakes and aquifers is renewed each year from rainfall and snow melt. The remaining amount of water is much larger, and for large lakes may actually be left over from the Ice Ages of long ago. This is water that is stored, and cannot be replaced if it is used. For example, it is estimated that only about one per cent of the water in the Great Lakes is renewed each year.

There is the same amount of water today as there was in prehistoric times. In other words, water is not an infinite resource.

Where Water Comes From
Water constantly circulates between the atmosphere and the earth. The rain and snow which falls as part of this hydrological or water cycle is the source of water for lakes, rivers and underground reservoirs. Some of this water is locked in permanent ice cover and glaciers.

Where Your Water Comes From
Where your water comes from depends on where you live. For instance, residents of PEI get all their drinking water from underground sources. In the prairies, water comes mostly from rivers and groundwater, but the supply is not always enough to meet demands for agricultural and household uses. In Nova Scotia and British Columbia, water is generally plentiful from many lakes, rivers and natural wells fed by an abundant groundwater supply. In Quebec, 45 per cent of the population draws its water from the St. Lawrence River.

Water Sustains Life
Water is used for much more than drinking. It is used for irrigation and livestock watering in agriculture, swimming and boating in recreation, or for industrial activities such as pulp and paper production.

In Canada's watersheds, all living things are connected to each other and the environment around them. These complex relationships are called ecosystems. Each body of water is a delicately balanced ecosystem that is always interacting with the surrounding air and land. In this way, water supports all life on earth.

Source to Tap
We recycle water - withdraw it, use it, sometimes clean it, and then return it to the lake or river to be used again by others downstream. This process is called "Source to Tap." It is a water-use cycle, similar to nature's water cycle of precipitation-to-ground-to-evaporation-to-precipitation again.

The "Multi-barrier Approach"
It is important that drinking water is kept clean, safe and reliable. In order to do so, the components of the water supply system-from source protection to the treatment and distribution of drinking water to consumers-need to be understood and managed as a whole.

Even though no approach will guarantee 100 per cent protection all of the time, it has been demonstrated that the most effective way to manage drinking water systems is to implement a multi-barrier approach. The multi-barrier approach is an integrated system that prevents or reduces the contamination of drinking water, from source to tap, in order to reduce risks to public health.

What Governments Do
To be effective, the multi-barrier approach requires commitment and co-operation from everyone involved. This includes elected officials and government employees, members of the water industry and the public. Governments work together, and with other partners, to protect our water resources by encouraging best management practices and making appropriate policies, regulations or laws. Through CCME, governments have committed to working together on research, monitoring and guidelines and best management practices.