Key Points:

Ohio is a leader in data center growth, with nearly 200 facilities already operating and nearly 80 more planned.

A new permit would allow data centers in Ohio to discharge untreated wastewater directly into rivers and streams.

Critics worry this allowance would bring about environmental degradation and threaten human health.

The Ohio Environmental Protection Agency is considering approving a new permit that would allow data centers across the state to discharge untreated wastewater and stormwater directly into rivers and streams, an allowance that is without precedent across the Great Lakes region. 

With this permit — which also applies to stormwater associated with on-site industrial activity, including chemical and fuel storage — the Ohio EPA concedes it is willing to sacrifice environmental degradation for the sake of business. 

“It has been determined that a lowering of water quality of various waters of the state… is necessary to accommodate important social and economic development in the state of Ohio,” the agency’s draft permit reads, referring to a federal antidegradation rule that allows some deterioration of high-quality waters if states determine it is justified by economic growth.

Environmental groups have voiced concerns that the permit — which would apply to any current and proposed data center regardless of its size, type, or location — fails to limit and monitor pollutants that place humans and the environment at risk.

“There’s a lot of unanswered questions about what is in data center wastewater discharge, where it’s going, and how it’s regulated,”

Helena Volzer, Alliance for the Great Lakes

“There’s a lot of unanswered questions about what is in data center wastewater discharge, where it’s going, and how it’s regulated,” says Helena Volzer, a senior source water policy manager with the Alliance for the Great Lakes. “This has been a minimized piece of the data center equation, and I think it deserves a little bit more attention.”

The Ohio permit would apply to water that circulates through data centers to absorb heat from servers, towers, and boilers. Recent investigations have shown that chemicals such as PFAS and nitrates, which are harmful to human health, are a part of these effluents, or untreated discharges. The chemicals are used in data center operations to prevent corrosion or microorganism growth. The concentrations in data center effluent are high enough to be concerning, but their environmental and human health impacts have not been adequately studied. Releasing warm, chemical-rich effluent has the potential to exacerbate the growth of algal blooms, critics say, a plight of particular concern in the Lake Erie watershed.

These compounds have drawn the attention of the federal government. In September, the U.S. EPA ordered a priority review of chemicals used in data centers, though many experts saw the move as a first step to fast-tracking their approval. 

“We inherited a massive backlog of new chemical reviews from the Biden administration, which is getting in the way of projects as it pertains to data center and artificial intelligence projects,” EPA Administrator Lee Zeldin said in a statement. “The Trump EPA wants to get out of the way and help speed up progress on these critical developments, as opposed to gumming up the works.”

As the Trump administration continues to roll back federal environmental regulations and push for AI investment, state agencies are increasingly on their own to manage the data center industry’s environmental footprint.

Surface waters in Ohio, such as those pictured here, would be vulnerable to untreated wastewater and stormwater discharges from data centers if the general permit is approved © J.Carl Ganter/ Circle of Blue

Ohio Data Center Growth

Nowhere in the Great Lakes basin has embraced the data center boom quite like Ohio. By one count the state has 195 such facilities currently operating and at least 77 campuses planned, the most potential new sites in the region. 

Environmental groups say local growth should come with more stringent environmental regulations. But the OEPA’s draft permit aims to do the opposite.

Currently, Ohio’s data centers pre-treat all wastewater according to local municipal standards, before discharging this water into wastewater treatment plants. The new general permit would instead allow data centers to discharge untreated wastewater directly into surface waters, without pretreatment. 

The OEPA has not provided a clear explanation on the shortcomings of the way things currently work, nor why this change is being made. It is also unclear which pollutants are currently flowing from Ohio’s data centers, as there is no rigid state mandate to track them. 

“We are not confident that the OEPA fully understands the scope of the types of contaminants that data centers might be discharging, nor are the data center operators themselves adequately aware of what they might be discharging,” Volzer says.

Advocacy groups have escalated these concerns internationally. In January, the nongovernmental organization Earthjustice submitted a letter to the United Nations special rapporteur on toxics and human rights urging the international body to discuss “PFAS-related human rights violations in the United States,” including those stemming from data center growth. 

The decision to relax wastewater treatment standards in Ohio is a contrast with the state’s closest regional competitor, Illinois, the only state in the basin with more existing data centers. Illinois lawmakers this month introduced new legislation that would more strictly regulate, track, and measure pollutants in data center wastewater. 

Ohio’s draft permit, on the other hand, does not require baseline water quality testing to determine whether discharges will degrade natural resources. The OEPA wrote that a provision in the state’s administrative code means the agency does not need to consider less harmful alternatives before allowing these discharges.

The permit’s statewide application is also under scrutiny. It would apply to all existing and proposed data centers — a one-size-fits-all approach that legal experts with the Ohio Environmental Council argue is both reckless and unlawful.

The proposed permit, issued under a Clean Water Act program, was first introduced in October, and the deadline for public comment passed on Jan. 16. An OEPA spokesperson told Circle of Blue that there is no timeline yet for a final ruling, as the agency continues to review the more than 7,000 comments submitted.

Meanwhile, lawmakers in Ohio have announced plans to introduce several new pieces of legislation to regulate data centers. Among these is an act that would prohibit these facilities from consuming more than 5 million gallons of water per day, require them to report annual water usage, and mandate they pay for all needed water infrastructure upgrades. But it does not address wastewater.

“Data centers use millions of gallons of water per day, and we hope to pass legislation that requires them to invest in local infrastructure and more efficient ways to use and reuse water,” state Sen. Nickie Antonio, D-Lakewood, said in a press conference last week.

Featured Image: State inspectors took samples and confirmed that water running into drains and ditches like this one near Edon, Ohio, had elevated concentrations of ammonia and nitrogen contamination found in manure. This drainage ditch, littered with several dead animals, including a deer and raccoon, channels water toward the Maumee River that empties into Lake Erie. © J.Carl Ganter/ Circle of Blue

Christian Thorsberg is an environmental writer from Chicago. He is passionate about climate and cultural phenomena that often appear slow or invisible, and he examines these themes in his journalism, poetry, and fiction.