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City of Philadelphia

Backflow Compliance

A cross connection is an improper and illegal plumbing arrangement between a potable and non-potable water supply. This connection, under certain hydraulic conditions, can lead to a dangerous "backflow" from a contaminated water system to drinking water.
The quality of Philadelphia's drinking water supply could be compromised if backflow from a non-potable supply containing hazardous substances occurs. The City of Philadelphia has Cross Connection Control Regulations to protect the public health and the integrity of its drinking water supply.

Cross Connection Control Resources

Cross Connection Information for Homeowners

Cross Connection Control Manual

City Approved Backflow Prevention Assemblies

The Backflow Assemblies that are approved for use in the City of Philadelphia, have gone through the approval process carried out by the University of Southern California Foundation for Cross Connection Control and Hydraulic Research (USC FCCC&HR) and are contained in the list below. 

Note: Only those assemblies having a rating of ≤0.25% Pb = “Y” (YES) are approved for use in the City of Philadelphia.


City Certified Backflow Prevention Technicians

City-Certified Backflow Prevention Technician Resource Guide
Technicians for Domestic Water Systems
Technicians for Fire Sprinkler Systems

Note: The foregoing lists of approved backflow assemblies and approved technicians are updated periodically.

Backflow Prevention Forms

Form CU100 - Facility Update on Backflow Prevention
Form CP100 - Backflow Prevention Assembly Installation Permit Application
Form CR100 - Certified Backflow Assembly Technician Registration Form
Form 79-770 - Backflow Prevention Assembly Test and Maintenance Record

Frequently Asked Questions