Because potable water is directly connected to these sorts of pumps (which could also have non potable water in them), many codes and municipalities require that a special backflow prevention device be installed. The check valve that comes with the pumps for example, is a type of back flow prevention device, but many municipalities and codes do not recognize that style as “approved” (at least at the time of this writing). We recommend you check with your local building department and if required, purchase the appropriate backflow prevention assembly to go with your pump. We always recommend a backflow device, and it is included in our pricing as well as the city fee when we furnish a water powered back up system.