Drnking Water-Sourc Protection
Halton-Hamilton Source protection region website
Documents and Maps>Maps

Provincial Mapping 

Use the new Source Water Protection Information Atlas  to show where the vulnerable areas are in relation to a property of interest.  Try it for your property here.

On the "Search By" page, type in your address, press search, and details will be displayed of which source protection area the property is located in, whether the property is within a vulnerable area to which source protection plan policies apply, with other information.  

Halton-Hamilton Source Protection Region Mapping 

The Halton-Hamilton Source Protection Region comprises the jurisdictions of Conservation Halton (The Halton Region Conservation Authority) and the Hamilton Conservation Authority.  The boundaries between the neighbouring conservation authorities were realigned slightly to reflect better the drainage patterns and the extension of the in-water area to the international boundary in Lake Ontario. Maps showing the two source protection areas are available for review and download here:

Many maps have been produced to visually show the outcome of the many delineations and assessments that are part of the source protection planning program and required by the Clean Water Act, 2006, its regulations, and the Technical Rules: Assessment Report.   

The vulnerable area mapping includes individual maps for each wellhead protection area and intake protection zone, as well as maps for the highly vulnerable aquifers and significant groundwater recharge areas at the Source Protection Area scale.  

Areas where significant threats are possible have also been mapped.  These areas are primarily within a portion of the wellhead protection areas.  The only significant threats outside of these areas are those identified through event-based modelling along the Lake Ontario shoreline and are part of the intake protection zones. 

The following maps are taken directly from the assessment reports and source protection plans:


Are you engaged in activities that could be significant threats to the drinking water sources in your community?  Find out by following the directions below to check your property.

The following wellhead protection area maps are pdfs with layers that include an aerial photograph as its base, the delineated parts of the wellhead protection areas based on time-of-travel of water at the surface of the ground to the well, the vulnerability scores assigned to the various portions of these areas, and coloured shading to show the extent of these vulnerable areas to correlate with the lists of possible significant threats to drinking water sources included in the legend of the map.  Click on the appropriate name of the well field in your community to open the map.  To activate the layers of the map, click on the third icon on the left of your screen as shown on the following illustration.  To open the folders click on the + sign or arrow beside Main and the + signs or arrows beside the other subfolders.  The eye at the left of each layer indicates that the layer is visible.  Click on the eyes to turn the layers off and on.  The zoom icon (labelled on the following illustration) will focus the map at your property when you click the icon and then draw the area on the map you’d like to zoom to.  Click on the pan icon when zoomed in and then click and hold the map while you push the map in the direction you’d like it to move.   


The areas where significant threats are possible are within WHPA-A (wellhead protection area  A, 100 m radius around the wellhead), WHPA-B (2-year time-of-travel for surface water to reach the well), and WHPA-C (5-year time-of-travel).  The areas shaded red have the maximum vulnerability score of 10 and all prescribed threats, except one, are potentially significant here. Group 1 of the list of potential significant threat activities included in the legend applies in this red area.  The area shaded orange has a vulnerability score of 8 and Group 2 of the list of potential significant threat activities applies here.

A group of chemicals called dense non-aqueous phase liquids (DNAPLs) pose a greater risk to groundwater sources due to the physical and toxic characteristics of the chemicals in the group. The protection area associated with them is the WHPA-C, within a 5-year time-of-travel. This area is shown on the maps by a pink outline and includes the WHPA-A and the WHPA-B areas.

Groups 4 (green hatched) and 5 (green) of the lists of potential significant threat activities apply only in the Carlisle surface water threat areas. Two wells in Carlisle have a close connection between surface water and the groundwater well source and the activities that could impact surface water in the vicinity of the well are also identified.


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This project has received funding support from the Government of Ontario.
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