Vulnerable Areas

Vulnerable Areas are areas where certain types of activities may pose a threat to drinking water quality or quantity.  The vulnerability of these areas is a measure of how easily contaminants may reach a surface water intake, or penetrate the ground to reach the aquifer supplying a well.  In the Essex Region, our drinking water comes from surface water intakes and the Vulnerability Areas are called Intake Protection Zones (IPZs) and Event Based Areas (EBAs).  Mandatory policies to protect drinking from certain threats apply in these areas.  We have also identified Highly Vulnerable Aquifers (HVAs) and Significant Groundwater Recharge Areas (SGRAs) that identify areas where groundwater would be susceptible to contamination, however, there are no mandatory policies that apply to these areas because groundwater is not used to supply municipal water treatment plants. Intake Protection Zones are areas of land and water where run-off from streams or drainage systems could carry contaminants that could impact the source water at the municipal drinking water intakes. Mandatory policies apply in Windsor’s IPZ-1 and IPZ-2 as well as the Belle River’s IPZ-1 and Amherstburg’s IPZ-1.  

• IPZ-1 – these are the areas closest to an intake where a spill would pose the greatest threat to sources of drinking water. The IPZ-1 is a 1km circle or semi-circle around the intake. Where the IPZ-1 abuts land, it includes a minimum setback of 120 m inland.
• IPZ-2 – these areas are just beyond the IPZ-1. The limits of this zone reflect the response time for the water treatment plant operator to respond to an emergency.  In the Essex Region, these are areas where water (and contaminants) could reach the intake within 2 hours.
• IPZ-3 – these areas extend outward from the IPZ-2 and include setbacks from all streams or drainage systems where modeling demonstrates that contaminant spills may reach the intake during an extreme rainfall or wind storm event. In the Essex Region, IPZ-3s include a 120m setback around all of our waterways, as well as some lands along the Detroit River shorelines and floodplain areas.

 The Event Based Area is an area where modeling has demonstrated that a spill from a specific activity could contaminate sources of drinking water. In the Essex Region, the EBA is the combination of IPZ-1, IPZ-2 and IPZ-3 for modeled activities (i.e. fuel spills).  The EBA covers an extensive area where mandatory polices related to the handling and storage of large volumes of liquid fuel apply. To determine whether your property is in a vulnerable area and what policies may apply, please use our interactive mapping tool. To see what’s happening in the rest of Ontario, please visit the Source Protection Information Atlas.