LANSING — Michigan environmental experts say that the state’s groundwater system is so expansive that it should be treated as a sixth Great Lake.
The state’s groundwater network contains as much water as Lake Huron, and more than half of all Michigan residents and businesses rely on groundwater day to day.
Michigan’s water use is partially regulated by the Great Lakes Compact, an agreement between Michigan and seven other states to conserve the region’s resources.
“The idea is that you don’t want to take out more than what is available to remove without actually causing an environmental impact,” said Lena Pappas, EGLE’s Groundwater and Geologic Services Manager.
Pappas helped develop a reworked tool that must be used by those making large water use requests. That work was highlighted in the 2025 State of the Great Lakes report.
She says that the modernized system will help ensure Michigan is holding up its obligations to the compact.
“The tools that we built, that I spoke about in the the report — it directly relates to our ability to be able to do that in a protective and efficient way, to provide those registration services for water users across the state,” she said.
Large-scale requests are defined as using more than 100,000 gallons of water a day.
The new system could be utilized by developers of data centers, which use large amounts of water to cool down computer parts.
Sara Pearson is director of the Michigan Geological Survey, a research institution that maps many of the state’s natural resources.
“Groundwater is something that we can’t see — you know, it’s easy to see a lake or stream, rivers — but there’s water that exists within the pore spaces in the soil beneath our feet or in the bedrock,” she said. “It’s really difficult to manage something when you don’t know how much you have and you don’t know where it all is.”
Pearson and her researchers are involved in developing other tools to help the state and water users better track the use of resources.
“We’re gathering all kinds of data and determining where the water is going, how it’s used in the communities, how much water is used,” she said. “And there will be a dashboard where you can create scenarios and determine where water might be needed.”