California usually leads the nation in the formulation of bad public policy—which policymakers in other states often see as a model. But this week, they actually did something worth emulating. They lifted a state ban on residential use of vinyl plumbing pipes, which are made with chlorinated polyvinyl chloride or CPVC. Unfortunately, it took the state more than a decade to lift this expensive, nonsensical mandate. The state's change of heart came after its housing department conducted a study debunking claims that the pipes are dangerous, which were posited by a coalition of environmental activists and plumbers' unions. In reality, the CPVC pipes are quite safe, energy efficient, and environmentally sound. They also cost much less—about a third of the alternative metal piping. These pipes are also very easy to install. CPVC installs with glue, rather than having to be soldered with a propane torch. Activists complain that the glue is dangerous—as if working with propane, an open flame, and hot metal is safer! The California housing board found that the risks associated with the adhesives is “less than significant” for workers who are exposed to the fumes on a regular basis. Apparently, plumbers need not fear the glue, but they might fear the ease with which homeowners can install—without having to hire a plumber. Activists and the plumbers' unions claimed a variety of other ills, which were rejected in the California study. Unfortunately, it is expected to take the state an entire year before they can change the building code to allow freedom to choose in plumbing. New York, Chicago, and a few other cities also maintain such bans. For once, they should follow California's lead—but they should move much faster.