Remember those old Olympia beer ads? “It’s the water.” When it comes to good beer, it really is the water, and that’s why Oakshire Brewing has begun its “1% for Watershed” program, donating one percent of the profits from its Watershed IPA in the lower Willamette Valley to keep the watershed and its water clean and healthy. In 2013, the McKenzie River Trust (MRT) will receive the funds to continue its restoration and conservation work.

Water is the number one ingredient in beer, and the water from Eugene’s McKenzie watershed is so pure that little to nothing has to be done to it before it’s used in the brewing process — breweries in many other areas have to purify their water. The less treated the water, the better it tastes.

A watershed isn’t just the water, it is the land and the water system and the linked living things within it (including human beer drinkers). Eugene’s water, drawn from the McKenzie River, comes clean and cold from snow atop the Cascade Mountains, which filters down through the lava rocks, bubbles up in springs, then flows through forests.

Joe Moll of MRT says that because craft beer is such a social thing for home brewers, professionals and the beer drinkers themselves, he’s seeing clean water and watershed conservation becoming “memes” within that culture.

With Oakshire’s “1% for Watersheds” program, one percent of the creamy and bitter IPA proceeds will go to the MRT in 2013 — stemming from a commitment to save the watersheds that help make Oregon an ideal craft brew region, from the water itself to the all-important hops that grow here. Several years ago, the Eugene Water and Electric Board, the Forest Service, conservation groups and local breweries dreamed up the idea of a “brewshed,” in which stakeholders in Oregon’s clean, pure water work together to protect that water from the effects of pesticides, industry, drugs, chemicals and everything else that could endanger it.

Brandi Ferguson, development manager for MRT, says support for keeping the watershed clean is spreading, just like Eugene’s locally brewed beers. She says she heard from an MRT supporter in Washington DC, who told her that he can buy Watershed IPA at his local Whole Foods and support the trust from the East Coast.

“Step by step, beer by beer, conversation by conversation, voices for the river are returning,” Moll says.

Now that Oakshire’s new tasting room has opened across the street from Wandering Goat in the Whiteaker, Eugeneans have even more convenient ways to drink for the watershed. Oakshire is hosting a “1% for Watersheds” party with McKenzie River Trust 5 to 8 pm Thursday, May 16, at the new tasting room, 221 Madison St.