Finding enough potable water to supply the needs of Minnesota's newest state park wasn't easy. The best well at Lake Vermilion State Park near Tower delivered a mere two gallons per minute, and the water had high levels of naturally occurring arsenic. Park planners and engineers eventually solved the problem by filtering water from 40,000-acre Lake Vermilion, but their search for solutions also inspired them to notch a first for Minnesota state parks—a graywater reuse system.

Graywater is used water that isn't contaminated with human or food waste. At campground shower buildings in Vermilion Ridge Campground, water from 12 sinks and six showers is filtered, treated, and reused to flush 10 toilets. The graywater system could conserve an estimated 135,500 gallons of water each season, according to DNR principal architect Peter Paulson.

The biggest challenge in adding graywater reuse to the park's shower buildings was getting a variance from the Minnesota Department of Labor and Industry's plumbing board, says Paulson, because current state rules prohibit it. Minnesota, being a water-rich state, has yet to formally change its plumbing code to allow graywater reuse.

The concern, says Cathy Tran, state plumbing plan review supervisor for the Department of Labor and Industry, is that graywater could accidentally be routed into drinking water pipes. Tran says special purple pipes were required to be used throughout the graywater system to eliminate the risk of accidentally mixing treated or untreated graywater with drinking water.

While CHS Field in St. Paul uses stormwater for irrigation and flushing toilets, Lake Vermilion State Park's graywater reuse system is the only one in the state that recycles sink and shower water, says DNR Water Use Program consultant Dan Miller. The new shower buildings, which also feature solar panels to heat water and reduce propane use, are up and running ahead of the park's official opening in late summer 2017, according to Dawn Voges, assistant manager at Lake Vermilion?Soudan Underground Mine State Park. The park has been in the works since 2010, when the DNR bought 3,000 acres of land and five miles of shoreline on the rugged southern shore of Lake Vermilion adjacent to Soudan Underground Mine State Park.

"We've been touting Vermilion as the next-generation type of park," says Voges. "We're the ones who get to find these green solutions. Hopefully we can take what works and move it out into other new park facilities as they are being built."