Vulnerable Areas

Vulnerable areas

There are four types of vulnerable areas named in the Ontario Clean Water Act, 2006:

  • Significant groundwater recharge areas or SGRAs
  • Highly vulnerable aquifers or HVAs
  • Intake protection zones or IPZs (for surface-water sources of  drinking water such as a Great Lake or large river).
  • Wellhead protection areas or WHPAs (protective zones around a  municipal well).

Highly vulnerable aquifers

An aquifer is more vulnerable to contamination if the soil layer is thin.

Aquifers are areas of soil or rock under the ground where cracks and spaces allow water to pool. They are considered highly vulnerable based on factors such as how deep it is underground, what sort of soil or rock is covering it, and the characteristics of the soil and rock surrounding it.

An image of a map showing highly vulnerable aquifers.
An image of a map showing highly vulnerable aquifers.

Significant groundwater recharge areas

The land area where the rain or snow seeps down into an aquifer is called a recharge area.

Recharge areas often have loose or permeable soil, such as sand or gravel, which allows the water to seep easily into the ground. Areas with shallow fractured bedrock are also often recharge areas.

A recharge area is considered significant when it helps maintain the water level in an aquifer that supplies a community with drinking water.

An image of a map showing recharge areas.
An image of a map showing recharge areas.

Do planning policies apply in this type of vulnerable area?

Source protection planning policies are only recommendations in highly vulnerable aquifers (HVAs) and significant groundwater recharge areas (SGRAs) of this region.

Policies do not have legal effect that requires property owners to comply in HVAs and SGRAs (except in a wellhead protection area Zone A, B, or C) as there are no assessed significant threats to drinking water in HVAs and SGRAs. However, municipalities, implementing bodies, and local people should have regard for these policies, developed locally and approved by the Province of Ontario.

Thank you for all you do to protect drinking water sources in all vulnerable areas. Take a look on this website at some of the ways you can protect drinking water sources with your positive actions at home and work.

For complete definitions, legislation, and regulations visit

For maps, local source protection plans, assessment reports, maps, fact sheets, and explanatory document, visit

Download maps now:

Site map for the Keeping Water Clean website: