While there is no comprehensive set of regulations for Washington State regarding cisterns, the following regulations for other states can provide a useful reference when designing a cistern. A reduced pressure backflow prevention device is required by the state of Oregon when both harvested rainwater and city water are used. This device prevents cistern water from flowing into the city water system. The Safe Drinking Water Act requires disinfection of water for general indoor use such as drinking, bathing, and cooking.

Other general guidelines include: locating cisterns at lower grade than the roof washer and far away from other potential contaminates such as septic tanks; the inclusion of an overflow device, as well as a device for dissipating inflow so as to not disturb sediment; and covering all openings with a screen to keep out mosquitoes and leaves.