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For over a century, the city of Rochester has pumped its drinking water supply from the Jordan aquifer — a massive, sponge-like underground formation spanning seven states, including the southeastern part of Minnesota.
As its population has grown, the city’s municipal utility has kept pace with demand by drilling new groundwater wells; about 30 of them now poke down into the aquifer anywhere from 400 to 1,000 feet below ground.
But the approach is nearing its limit, state officials say.
The Minnesota Department of Natural Resources notified Rochester Public Utilities in 2024 that it cannot add any additional wells within city limits because they could imperil streams and wetlands reliant on groundwater. The decision has prompted a long-term study by the city of how it can expand its water supplies to keep up with continued growth.
“We’re looking out over a 40-year period, roughly, of continued [population] growth, and studying if we continue to use the Jordan aquifer and potentially expand the usage of it, what impacts does that have?” said Tim McCollough, the municipal utility’s general manager, who said the state’s 2024 decision did not come as a total surprise.
In a state famous for its abundant water, Rochester’s study foreshadows a conversation that’s likely to become more common in coming decades as state and local officials grapple with water stressors, from data centers and industrial development to climate and land-use changes.
“We’re a little spoiled” in Minnesota when it comes to water, said Carrie Jennings, a geologist and policy and research director for Freshwater, a nonprofit water advocacy organization. “But things are changing and there’s going to be more climate stress, different styles of rain events, different needs for water use.”
Groundwater a source of pride in Rochester
Rochester’s growing population of about 125,000 residents currently uses 4.8 billion gallons of water every year, a number that is predicted to almost double by 2065, according to the local utility. The maximum amount of water the city can draw from the Jordan aquifer is 5.7 billion gallons annually, which it expects to hit within the next five years.
The state limit is based on how much can be withdrawn without impacting surface waters, including regional streams that are popular with anglers and a rare type of wetland known as a fen that serves as critical habitat for rare and endangered species.
Related: What’s a fen? This rare wetland is why southeastern Minnesota can’t endlessly pump groundwater
A similar issue emerged just over a decade ago in White Bear Lake, where in 2013 the suburb’s namesake lake dropped to a record low because of overpumping from groundwater wells. Nearby Woodbury has also been monitored closely by the Department of Natural Resources for how much water its wells are pumping.
“Woodbury is one of the suburbs that has really exploded in the last two decades in terms of population, so they’ve added a lot of wells,” said Tony Runkel, lead geologist of the Minnesota Geological Survey at the University of Minnesota. “It’s really quite analogous to Rochester, and the concern [in Woodbury] has been: will those water withdrawals decrease the groundwater contribution to the streams?”
The fact that Rochester still uses groundwater is in itself unusual: most large cities use surface water from rivers and lakes. That’s because surface water fills up much faster than groundwater, which can take years or even decades to recharge. The Twin Cities once relied on groundwater, but switched over to surface water from the Mississippi River as the metro area grew.
Transitioning to a surface water model to support the growing water demands is one option Rochester Public Utilities is exploring, but some city officials are resistant to the idea.
“I know there are people in the community who would say you’re the only large municipality that doesn’t use any surface water, you’re the only one that doesn’t do any sort of major treatment center,” said Patrick Keane, a Rochester city council member. “I take those as almost bragging things that we’ve got good quality water without all that treatment.”
The utility has identified two manmade reservoirs in the Zumbro River as potential surface water sources, but Keane worries it would not provide enough water to support Rochester. The Mississippi is another option, but it lies about 40 miles away from Rochester, creating a transportation challenge.
If the city were to switch to surface water, it would also have to build a new water treatment facility, which would be a multimillion dollar construction project.
“I really do worry cost-wise, but also just the logistics of doing surface water,” Keane said.
The utility has also considered mixing surface and groundwater, a less common process that would also require building a new treatment plant that could handle both water sources. City officials appear to be more interested in maintaining groundwater as their sole source of water because of the high cost of treatment facilities.
“I am still optimistic that we will find a groundwater solution because blending different sources of groundwater is a more manageable process than trying to blend surface water and groundwater,” said Todd Blomstrom, assistant general manager of Rochester Public Utilities in a city council meeting on July 27. “I’m hopeful that we will remain a groundwater system.”
Questions of taste, cost and sustainability
In order to remain solely reliant on groundwater, Rochester is looking at drawing from deeper sources: the Wonewoc and Mt. Simon aquifers. These aquifers would be used to supplement the water Rochester currently pulls from the Jordan aquifer.
But drilling deeper wells concerns geologists who call the process a form of mining. Groundwater from the Mt. Simon aquifer is estimated to be 60,000 years old and is referred to as “fossil water.” If Rochester were to tap this water, it would be drawing from a non-renewable resource.
“It’s not coming into the ground very easily, and once it’s gone, it’s gone,” Jennings from Freshwater said.
Protecting this water is important to locals like John Meyer, a farmer outside of Rochester who uses private wells on his farm. Meyer farms with cover crops in order to improve soil health, thus improving the water quality and quantity of the groundwater below him.
He’s critical of the plan to drill deeper wells, saying it just seems to “delay” the inevitable — groundwater depletion and contamination from the surface.
“It takes a long time for what we do up here to affect that area we’re pulling from, and if we go deeper, we’re just delaying that process” but not fixing it, Meyer said. “The smart thing to do is correct what we’re doing up here on top.”
Correcting what’s happening on top could mean rethinking the way Rochester currently uses its water. Rochester Public Utilities encourages water users to practice conservation habits like opting for more efficient appliances, establishing smaller lawns and watering less, but these practices are all voluntary.
Related: Minnesota agencies planning ahead for changes to state’s water supply
The city has not implemented the watering restrictions other parts of Minnesota enforced this summer as severe drought conditions affected much of the northeastern part of the state, according to the Department of Natural Resources’ drought monitoring map.
But as water resources become more scarce — especially with climate change, industry and population growth, and land use changes — planning for a new water reality will likely be necessary. Councilmember Keane said he’s glad Rochester is having this conversation now, not in five years from now once the city has already closed in on its appropriation limit.
“We’re not dealing with it under duress,” Keane said. “We’re dealing with it as just good stewards of our natural