A Note from the Fund:

We are pleased to share this guest blog from Amanda Grimm, GIS and Data Manager at the Great Lakes Commission. Amanda’s team created a new interactive mapping tool and binational, basin-wide database of wastewater and stormwater outfalls in the Great Lakes. The resource provides valuable information about wastewater and stormwater systems throughout the basin and will support regional partners working to improve wastewater treatment and address discharges. Creating it was no small undertaking. As Amanda writes, “With two countries, eight states and two provinces, getting a basin-wide picture of Great Lakes wastewater infrastructure is difficult.” Her team rose to the challenge, producing an easy-to-use tool unique to the basin, along with a user guide. We hope the tool becomes a widely used resource.

Shannon Donley, Senior Program Lead
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Great Lakes Wastewater Discharge Inventory

If water remembers where it has been, then wastewater treatment makes sure that it forgets our worst habits before it returns to our rivers and lakes. Decades of investment and stronger environmental protections have significantly improved treatment processes, protecting both public health and the environment. However, wastewater discharges still contribute to pollution, and aging infrastructure remains an ongoing challenge for communities across the region.

With two countries, eight states and two provinces, getting a basin-wide picture of Great Lakes wastewater infrastructure is difficult. To help fill that gap, the Great Lakes Commission created a new inventory that brings together consistent information about municipal wastewater treatment facilities across the region. The inventory, available through a new online dashboard, includes all municipal treatment facilities that currently discharge into the basin, along with details like discharge volume, treatment level, population served, regulatory compliance, and whether they experience combined sewer overflows (CSOs), which can release untreated wastewater during heavy rain events.

To build that regional picture, the inventory brings together and reconciles information from U.S. EPA and Environment and Climate Change Canada, then fills the gaps using data from Great Lakes state and provincial agencies as well as individual wastewater facility operators. Most of this information was already publicly available, but it was scattered, sometimes difficult to access, and reported using different formats, units, and terminology. By bringing these sources together and standardizing key details, the inventory makes it easier to compare facilities across the region and identify patterns, strengths, and potential gaps in how wastewater is managed. 

The interactive dashboard turns the inventory into a practical tool for exploring wastewater infrastructure across the region. Users can browse and filter facilities on a map; review details such as discharge volume, treatment level, effluent limits, and regulatory compliance; and export data for further analysis. Individual outfalls are also mapped, including CSO outfalls. The wastewater inventory is available through the Great Lakes Commission’s new data portal, data.glc.org, where users can explore this and other regional datasets and tools.

Development of the inventory and dashboard was supported by the Great Lakes Protection Fund.

—GLPF wishes to thank Amanda Grimm for this post