Is a back-flow preventive device required?
A. Some local plumbing codes require back-flow preventive devices on many water fixture installations to protect the potable water supply in the event of a flow-reversal in the system. Check with your local plumbing department if you have any questions about back-flow. Typically a Dual Check Valve or a SVB (Spill-Resistant Vacuum Breaker) are industry recognized Back-Flow devices that can be installed in the water supply pipe before Basepump. Basepump poses no threat to the potable water supply. It is open to the atmosphere on the discharge side and also has an integrated backflow device that prevents the reversal of water flow through the ejector valve.
