Section 610.1/Water Supply Protection (Backflow Prevention)
UPC 610 covers backflow prevention requirements including device types based on degree of hazard.
The potable water supply must be protected from contamination by backflow through cross-connections. The type of backflow prevention device depends on the degree of hazard. High-hazard connections (sewage, chemical systems, medical equipment) require a reduced pressure principle backflow preventer (RP) or an air gap. Low-hazard connections (fire sprinkler systems with no chemical additives, irrigation without chemical injection) may use a double check valve assembly (DC). Atmospheric vacuum breakers, pressure vacuum breakers, and hose bibb vacuum breakers are permitted for specific applications per Table 603.2 of the UPC.
Why this section exists
Backflow contamination of the potable water supply is a public health emergency. When water pressure drops (a water main break, fire hydrant use, or pump failure), contaminated water from connected non-potable systems can be siphoned back into the drinking water supply. The UPC backflow requirements parallel the IPC requirements but reference UPC-specific tables and device standards. In western US states that adopt the UPC, these provisions govern the backflow prevention design.
What plan reviewers look for
Plan reviewers identify every cross-connection on the plumbing drawings and verify the correct backflow preventer type per the UPC tables. They check the building supply for a backflow preventer if required by the water purveyor. They verify that irrigation, boiler makeup, cooling tower, and fire sprinkler connections all have appropriate devices. They also check accessibility for the annual testing required on RP and DC assemblies.
Common violations
Related UPC requirements
Table 603.2 lists the approved backflow devices by application. Section 603 covers water supply design including pressure considerations with backflow preventers. IPC Section 608 provides the equivalent backflow requirements for IPC jurisdictions. The local water purveyor may have a cross-connection control program with additional requirements.