Channel 9 discovered proposed change in language in a North Carolina law being debated that could allow Duke Energy to contaminate more water near Mountain Island Lake and Lake Norman.
Those areas provide drinking water for Charlotte and many other local cities.
State law enforces what is called a compliance boundary, where companies are allowed to exceed safe limits for contaminants like arsenic.
The bill allows an oversight committee to change it from 500 feet from the source of contamination to a company's property line which could go for miles.
Environmental watchdogs said that could endanger your health.
Catawba Riverkeeper Rick Gaskins explains why expanding the compliance boundary for Duke Energy's coal ash ponds in Charlotte concerns him and should concern residents.
"Duke owns the property under the lakes. They could contaminate all that land under the lakes and let it spread and spread and spread," Gaskins said.
The North Carolina Seirra Club agrees saying, "For coal-fired power plants and industrial facilities that own property on both sides of a river or lake, this effectively authorizes the contamination of the groundwater." It's concerning for people Channel 9 found on the lake Tuesday.
Fisherman Mike Craft doesn't want the change.
"It's very important. It's what we drink," Craft said. "If it has arsenic, it's bad for the fish and humans."
"I live on this, I play on this, I want to see it kept pristine," Craft said.
A Duke Energy spokeswoman told Channel 9 if the bill does pass, the state still has the ability to restrict boundaries and said it will keep Duke's boundary at 500 feet.
But Gaskins thinks under the Republican-controlled Congress, eventually it will.
"They could arguably contaminate the whole lake under this language," Gaskins said.