If trendy craft beers are your thing, you might occasionally lift your glass to California. The Golden State, cradle of the craft brew movement, leads the U.S. in the number of craft breweries and number of craft beer barrels produced each year.

PhotoBut that could change as the American West continues to face the possibility of severe drought.

California’s drought, the worst in 1,200 years, persists despite recent rainfalls. The state’s reservoirs remain at only 62 percent of capacity. And in the long run, scientists predict, climate change will bake the Southwest, making it even hotter and drier than it is today.

That’s a problem for brewers, as beer is made of 90 to 95 percent water. Producing one gallon of beer can require upwards of 15 gallons of water, depending on the efficiency of the brewery, so California’s shrinking rivers and groundwater supplies worry craft brewers.

Master Brewer ‘Extremely Concerned’

“If things continue to be dry for several more years, we’re extremely concerned about our future in this area,” says Peter Kruger, master brewer at Bear Republic in Cloverdale, California.

The result? Brewers are flocking to the East, where the outlook for adequate water supplies is more secure.

Already, Sierra Nevada — the Chico, California-based company that pioneered the craft beer movement — has opened a second location in the mountains of western North Carolina.

New Belgium, of Fort Collins, Colorado, and Oskar Blues, of Lyons, Colorado, have also expanded to western North Carolina within the last two years and set up shop within 40 square miles of each other.

Green Flash Brewing, based in San Diego, California, broke ground on a second location in Virginia Beach in late 2014. Stone Brewing of Escondido, California has also announced plans to expand to Richmond, Virginia.

“The climate is obviously shifting and we have to shift our behaviors to adjust to that,” says Cheri Chastain, sustainability manager for Sierra Nevada. “The availability of water is one thing that we absolutely cannot be caught off guard with. Without a supply of water, we can’t make beer.”

A Craze Is Born

The definitions of “craft” and “microbrew” vary, but these types of beer generally are produced by independent brewers in small quantities. Craft brewing pioneer Fritz Maytag launched the craze in 1965 when he purchased and reinvented Anchor Brewing Company in San Francisco. Ken Grossman, under Maytag’s tutelage, founded Sierra Nevada Brewing in the late 1970s.

In the decades since, craft beer sales have risen astronomically. Today, California boasts the largest number of craft breweries in the country (381) and the most barrels of craft beer produced per year (2.9 million), while Colorado ranks third in number of barrels produced annually. The total economic impact of craft brewing in the Southwest was $7.9 billion in 2013, according to the Brewers Association.

Those dollars are what the Southwest sees at risk as breweries expand in the East, citing reduced shipping costs in addition to better water availability.

Stable Water Supply in the Smokies

At the new Sierra Nevada brewery in Mills River, North Carolina, gleaming copper letters emblazon the building’s façade. Large rain barrels punctuate the front of the building, which is surrounded by the forested expanse of its 218-acre campus.

The fact that some breweries are congregating in western North Carolina is no accident. The region already has a burgeoning craft-brew culture: Asheville, North Carolina, reigned as “Beer City USA” four times from 2009 to 2012. And significantly, the region’s swaths of protected forests help ensure a high-quality and plentiful water supply.

Since water is the main ingredient of beer, water quality and chemistry are major factors in flavor, brewers say.

“Clean water makes great beer, and we have some of the cleanest water in the country,” says Drew Stevenson, communications manager for the Asheville-based Highland Brewing Company.

An Economic Boost

The breweries’ moves are a gain for western North Carolina’s economy. New Belgium and Sierra Nevada — the second and third-largest craft beer companies in the country — each spent $100 million or more constructing their new campuses.

Sierra Nevada’s North Carolina campus has nearly 100 full-time employees, and New Belgium has announced plans to hire 140 workers.

The region, already dependent on tourism, also stands to gain in that arena. Sierra Nevada is aiming to become a beer destination in the area and has built a taproom, restaurant, and event space, along with plans for miles of biking and hiking trails, on its campus.

Likewise, Oskar Blues, which says 40 percent of its sales are a result of tourism, has constructed a concert venue and event space, along with a bike farm — a mountain biker’s haven with miles of biking trails and jumps.

Threats to Water in The East?

Still, the future of abundant and high-quality water in western North Carolina is by no means assured. In November 2014, the U.S. Forest Service proposed industrial logging on 700,000 acres in the Pisgah-Nantahala National Forests that surround Asheville, and some fear the potential impacts on water quality.

Could the breweries themselves pose a threat to water supplies? Actually, says Katie Hicks, assistant director of the non-profit advocacy group Clean Water for North Carolina, breweries often make for good allies in protecting water because it is so important to their product: “They’re often willing to jump into advocacy fights.”

But Hicks sounds a word of caution: “One big concern is that water is very plentiful in certain parts of the mountains, which could lead to struggles in the future if neighboring regions are low on water.”

Sara Peach, an environmental journalist and regular contributor to Yale Climate Connections, teaches environmental journalism at the University of North Carolina at Chapel Hill. Ellie Crane is a senior environmental studies major at the University of North Carolina at Chapel Hill.