It's a question of how clean the water flowing into Lake Wylie is, and what's in the water consumed by almost all of York County.
Two groups that spend as much time as anyone laboring over that water, offer widely different answers.
The North Carolina Department of Environmental Quality is taking comments through Friday on a draft permit outlining what Duke Energy can discharge from Allen Steam Station. Allen is a coal-fired plant in Gaston County, on the northern part of Lake Wylie in Belmont.
The Catawba Riverkeeper Foundation wants to add public pressure to the process, calling on citizens to ask for stricter rules.
"This permit is unacceptable, especially with all we have learned about coal ash in recent years," said Riverkeeper Sam Perkins. "Why in 2018 are we still allowing unlimited amounts of pollution to be dumped into our drinking water reservoir?"
Duke Energy, which runs the plant and manages the Catawba River and its lakes, contends the draft permit is a needed step in maintaining good water quality in the lake. Including, said company spokesperson Erin Culbert, the issue of coal ash basins.
"It's ironic that special interest groups are opposing the very permits that are essential to move forward with safely closing ash basins," she said. "Strict standards in the draft permit ensure that Lake Wylie remains protected for all who rely on it."
Most of York County relies on it. Rock Hill, downstream of the Allen site, withdraws water which travels through public and private pipes to serve most of the fast-growing county. Rock Hill, Fort Mill, Tega Cay and other municipal systems use the water, as do private ones like Carolina Water Service in Lake Wylie.
Coal ash, a contaminant-rich byproduct of coal-fired plants, has been a concern for at least a decade. Ash ponds are typically located on the same water sources the coal plants themselves are.
In 2008 a coal ash site in Tennessee failed, releasing 300 acres of material and prompting closer looks at site nationwide. In 2014 almost 40,000 tons of coal ash spilled from a Duke-owned steam station in Eden, N.C.
Perkins said the proposed permit is "disturbing evidence" that Duke the and state agency haven't "learned lessons from past and ongoing contamination problems with coal ash." Perkins called it "baffling" the state wouldn't limit or require sampling for some contaminants.
"Especially given that Lake Wylie is a drinking water reservoir for more than 100,000 people downstream in York County and beyond," he said.
The draft permit, Perkins said, doesn't limit arsenic, selenium, mercury or lead. Nor, he said, is monitoring required for cobalt, chromium, radium and other potentially toxic materials.
The idea that Allen's discharges aren't thoroughly tested, Culbert said, isn't true.
"The draft permit absolutely requires routine monitoring for many substances, including selenium, arsenic and mercury," she said. "It does not have a prescribed limit for some, because the amount we release does not present a risk to water quality in the lake."
Other elements that aren't monitored aren't, she said, because they aren't prevalent in coal ash. Some occur naturally. Duke's permit focuses on the elements required by state and federal regulators, and issues with limit amounts or additional testing are in fact issues with environmental agencies, Culbert said.
Perkins believes the Allen permit isn't as strict as permits at other Duke sites, including for its Riverbend station on upstream Mountain Island Lake. The Allen permit is "significantly weaker" than a previous draft permit for the same site, he said. Perkins also has concerns about Duke's management of seeps into the lake, something common to earthen dams.
"Duke says they can responsibly manage these into the future, but they have had decades of chances and have failed to do so," he said.
Culbert said her company already signed a consent order to eliminate seeps at Allen. The new permit, she said, will help.
"The most effective way to do that is to remove water from the basins, which is exactly the purpose of this permit," she said. "The draft permit includes engineered seeps so that they can be monitored and controlled."
Seeps "represent small amounts of water," she said, and testing nearby waterways shows seeps don't impact water quality in the lake.
While their ways of getting there are different, both the foundation and utility want to get to the same place. Both want clean, reliable water in the lake.
Whether to excavate, recycle or close ash basins is a site-specific question Duke has to make, Culbert said.
"For the ash basins at the Allen plant, excavation would represent more than two decades of truck trips to relocate that material," she said. "Not only does that far exceed state and federal deadlines, it burdens the local community with air emissions, disruption and safety risks while impacting a broader environment."
Three units at Allen are set to retire by the end of 2024.
Duke proposes building a retention basin this year to reroute streams currently discharged to the ash pond. That move is part of the decommissioning of the ash pond, required by the Coal Ash Management Act in North Carolina.
Want a say?
Public comments can be mailed to Wastewater Permitting, Attn: Allen Permit, 1617 Mail Service Center, Raleigh, NC 27699-1617. Comments can be emailed to firstname.lastname@example.org with "Allen" in the subject line. All comments must be received by May 18 to be included in the official record of the draft permit.