If Jesus had been a Portlander, he might well have chosen to turn water into beer. After all, a big reason Stumptown is the nation’s Holy Land for microbrewing stems from our superior water, courtesy of the Bull Run watershed.

Brewers in other parts of the country who rely on water containing taste-fouling amounts of minerals like calcium and magnesium must constantly filter it. But Bull Run water is almost solely rainfall and snowmelt, and, for the purposes of making beer, “absolutely pure,” says Jeff Edgerton, assistant brewmaster at Bridgeport Brewing Co.

Little wonder then that some of the city’s brewers took to the front lines this summer to fight the Environmental Protection Agency’s attempts to mess with our beer’s liquid terroir. The EPA’s Long Term 2 Enhanced Surface Water Treatment Rule (dubbed “LT2”) mandates that by 2014 every public drinking water system in the country be treated at its source for Cryptosporidium, a nasty microorganism that can cause a bad case of Montezuma’s revenge—or even death.

Never mind that the bug hasn’t been detected in Portland’s water supply since 2002. And funding an expensive treatment plant—between $100 and $385 million depending on the type—meant an 18 percent water rate hike starting in July. That’s no small thing if, like the Widmer brothers, you use nearly 40 million gallons of water every year. But the Widmers are more concerned that the changes could affect taste.

“Beer is 90 to 95 percent water,” says Kurt Widmer. “And after spending nearly half-a-billion on a filtration plant, no one could tell us what the water would be like.”

After a Widmer-led political blitz, Portland’s city council voted in July to pursue a UV treatment plant, which zaps “crypto” bugs with high-powered lights instead of using direct filtration, which often adds chemicals to the water. Meanwhile, the water bureau is working to secure an exemption for Bull Run to the EPA’s LT2 filtration requirement.

But Bull Run’s sacredness to beer may be more religion than science. Brian Dunn, owner of Great Divide Brewing Co. in Denver, notes that his water comes from as many as four different places, but that it doesn’t affect the quality of his beer. In fact, despite the changing water, Great Divide has still collected 13 Great American Beer Festival medals and four World Beer Cup awards.

And even if Portland’s water comes with a new flavor, some brewers, like Hair of the Dog’s Alan Sprints, are ready to embrace it.

“My mission is to make Portland, Oregon, beer,” he says. “So whatever water we have here in Portland, then that’s the kind of beer I am going to be making.” We’ll happily drink to that.