Several communities are enacting regulations and guidelines for dealing with rainwater harvesting. In Arizona, the towns of Tucson, Flagstaff, Chino Valley, and Pason have enacted ordinances encouraging the use of harvested rainwater. In Washington state, Seattle and Friday Harbor, as well as King County, have recently established their own guidelines.
Currently, the American Rainwater Catchment Systems Association is working with several national organizations to come up with general ordinances that communities can revise and adopt. Texas has state legislation dealing with rainwater harvesting and, along with Hawaii and Virginia, offers rainwater harvesting guideline booklets (see Access).
The Uniform Plumbing Code has an appendix dedicated to rainwater systems, with sizing guidelines for gutters, downspouts, and lateral pipes. The applicable plumbing code should be reviewed for any design of rainwater conveyance systems.