All Mark Miller wanted to do was wash some cars and water the grass in front of his new car dealership.

As the proprietor of Utah’s first LEED-certified, environmentally friendly car dealership, Miller wanted to minimize his reliance on water from Salt Lake City’s public utility. So his extensive remodel of the building included two large new cisterns designed to capture rainwater for irrigation and car washing. But Miller was surprised to learn that trapping water on his own roof would be illegal.

“The state said no,” he explains. “In order to use the system, we had to have an existing water share. It’s ludicrous.”

Miller is not the only water-conscious Westerner to run afoul of the region’s prior-appropriation doctrine. Conservation advocates, including many utilities, have embraced the idea of using water collected from roofs, and stored in cisterns or rain barrels, to reduce reliance on dwindling surface water or groundwater supplies. Yet in Utah, Colorado and Washington, it’s illegal to do so unless you go through the difficult — and often impossible — process of gaining a state water right. That’s because virtually all flowing water in most Western states is already dedicated to someone’s use, and state water officials figure that trapping rainwater amounts to impeding that legal right.

No one actively enforces these laws, as Boyd Clayton of the Utah Division of Water Rights notes: “We’re not like cops out looking for speeders. Spending time enforcing these cases is not a priority.”

As a result, would-be water harvesters often learn about potential legal trouble only when they try to do the right thing, as Miller did, by asking for a state permit. That’s what happened to Kris Holstrom, who runs an organic farm outside Telluride, Colo. The well she’s relied on for years provides less water than it once did — a change she attributes to drought and increased development. So she asked the Colorado Division of Water Resources for a permit to collect runoff from building roofs — and was denied.

Full Story: http://www.hcn.org/issues/40.18/a-good-idea-2013-if-you-can-get-away-with-it