Water from the Las Vegas Valley Water District is considered “very hard”—like many Western cities’ water supplies. The hardness is about 290 parts per million (ppm) or 17 grains per gallon. Hard water results from high levels of dissolved, non-toxic minerals—in our case, calcium and magnesium carried into Lake Mead from the mineral-dense Colorado River. Tenaya Creek Brewery has an award-winning Pilsner, a beer style originating from the Czech Republic. That area’s water is considered remarkably soft, so how do they make it work a world away? Reverse osmosis (RO) is a water purification process in which water is forced through a semipermeable membrane that removes 90-99% of tap water impurities. The result is water that is free of minerals and other contaminants. The membrane type determines the amount of dissolved solids a unit is capable of removing. The water is then rebuilt by the brewer, adding elements to influence aroma, taste, and mouthfeel.