Water Capacity Issue Reveals Need to Increase Protections for Groundwater; Transparency and Accountability Needed
Wellhead Protection Areas map, Region of Waterloo. Wells in the Mannheim area are circled in red.
December 15, 2025
Kitchener, ON / Territory of the Chonnonton, Anishinaabe, and Haudenosaunee — On December 4th, the Region of Waterloo announced a water capacity issue within the Mannheim Service Area. It also stated that the region would immediately stop reviewing development applications while a third-party review of the water system occurs. Few other details have been provided.
Hold The Line WR is gravely concerned about this surprise threat to Waterloo Region’s drinking water supply, and we urge the Region to provide additional context and clarity as to the nature of the issue.
The term “Mannheim Service Area” did not appear anywhere on the Region of Waterloo’s website prior to December 4th, nor does it appear in the current Water Supply Master Plan. As such, we do not know what the Region means when it says “a water capacity issue has been identified within the Mannheim Service Area”.
The Mannheim Water Treatment Plant (located near the border between Wilmot and Kitchener) is a core part of the Region’s water supply infrastructure and is the most significant source of water feeding into the Integrated Urban System — a network of wells, treatment plants, and pumping stations that connects Waterloo, Kitchener, and Cambridge (as well as some rural communities).
Section 1.1 of the Water Supply Master Plan states: “Treated surface water and disinfected groundwater from nearby wells is collected in the Mannheim Reservoir and conveyed to the distribution system by the Mannheim Zone 4, 5, and 6 PSs”
Section 1.6 further states, “Interconnectivity between some pressure zones allows water to transfer between zones at select locations to meet demands.”
Given the lack of details provided by the Region, we can only infer that the Mannheim Water Treatment Plant is not receiving enough supply from groundwater wells and the Grand River, or that there are problems with the interconnectivity between pressure zones, or both. We urge the Region to provide additional clarity in this matter.
When we look at the development pressures around Mannheim, we note the proliferation of gravel mining operations in Wilmot and North Dumfries, which consume vast amounts of water and threaten the ability for aquifers to replenish. We further note that when the Province issues mining permits, it does not consider the cumulative impact of these mines on groundwater.
Residential and industrial development in greenfield and agricultural areas is also a major cause for concern. By paving over land for new subdivisions in southwest Kitchener and the Wilmot land assembly, we risk further exacerbating the capacity issues at the Mannheim Water Treatment Plant.
Our region is the largest urban community in Ontario relying almost exclusively on groundwater. In recent years, we have seen a chipping away at policies that protect our water recharge areas and the countryside. Dangerous development proposals in areas like Big Springs Farm and the Wilmot land assembly cannot be allowed to continue. With this recent revelation of a water capacity issue, we must re-commit to growth planning that protects our Countryside Line and groundwater aquifers.
The residents of Elmira know the consequences of water mismanagement — the village has still not recovered from its water contamination crisis over 35 years ago. Protecting our wells, whether from further contamination or from depletion, is an existential necessity.
We can’t wait for the results of a third-party review before taking steps to respond to this water capacity issue. Therefore, we present the following calls to action:
We call on the Region of Waterloo to disclose the nature of the water capacity issue, when it was first identified, and how it impacts each part of the Integrated Urban System.
We call on the Region of Waterloo to end the Land Assembly in Wilmot and commit to long-term agricultural use of those lands owned by the Region.
We call on the Province of Ontario to issue a moratorium on all new aggregate mines and any below-water aggregate mining in Waterloo Region.
We call on area municipalities to pause approvals for all new plans of subdivision and development applications in Designated Greenfield Areas, until the Region of Waterloo is able to continue its participation in the development review process.
We call on area municipalities to implement Official Plan policies that protect groundwater recharge areas, including the Countryside Line, Environmentally Sensitive Landscapes, and the Protected Countryside designation.
Signed,
Grand River Environmental Network
Hold The Line Waterloo Region
Waterloo Region Yes In My Backyard
Media contact: Sam Nabi, Hold The Line WR connect@holdthelinewr.org 226-988-4137