Since the 1990s, there's been a strange phenomenon happening in cities throughout the West. Their populations are booming, but their overall water use is staying the same, or in some cases it's going down. As part of our series on urban water conservation, KUNC reports that a lot of credit for the savings should go to... the toilet. This story is part of a collaborative series from the Colorado River Reporting Project at KUNC, the Mountain West News Bureau, and Elemental: Covering Sustainability.