The source of drinking water for 48 million people is one of the Great Lakes, the rivers and smaller lakes located within the watershed, or one of the groundwater aquifers flowing beneath them. Many of these sources are shared across city, county, state/provincial, and even international borders. Blue Accounting provides information about threats to these sources of drinking water, as well as strategies and investments being implemented from the local to international level to mitigate them.


of the Great Lakes population who rely on public water systems are protected from a source water protection plan


of US public water system users within the Basin drink water that periodically is tested for selected unregulated contaminants through a US EPA monitoring program


of inland drinking water sources draw from watersheds impaired by nutrients

Download the Source Water fact sheet here. 

Our goal is to protect sources of drinking water in the Great Lakes Basin from multiple threats in order to assure a safe and sustainable supply of drinking water for all Great Lakes Basin residents. To that end, the Source Water Work Group has identified the top Basin-wide threats to drinking water sources. They are:

  • Nutrient Impacts

  • Insufficient Management Strategies and Planning Efforts

  • Spills

  • Contaminants of Emerging Concern

As stewards of the largest freshwater system in the world, the residents of the Great Lakes and St. Lawrence River Basin are rightfully proud of this shared natural resource, but struggle to find consistent ways to track progress toward a collective desire for a safe and sustainable drinking water supply. Blue Accounting’s Source Water issue works with water professionals from around the Basin to track progress on reducing multiple threats to drinking water including nutrients, spills, and contaminants of emerging concern, while also tracking preventative efforts like management strategies and planning.

More About Source Water

How we Work

Blue Accounting has identified the top Basin-wide threats to drinking water sources and is working to share information about strategies and investments that mitigate them and measure progress in reducing the these threats.

Who’s Involved

This work is guided by a diverse, binational work group of water professionals from across the Great Lakes region that reflects the breadth of interest and experience in source water protection.

Where We Work