Cross-Connection & 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 Situations at Home

Bad habits in your home can create what plumbers call a “cross connection.” Cross connections can allow dirt, unsafe water and chemicals to get sucked into your drinking water. This is called “backflow,” and it can make you and your neighbors sick.

Cross Connection Control Manual

Updated 2017

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.

List of Approved Backflow Assemblies

City-Certified Backflow Prevention Technicians

Note: The list of approved backflow assemblies is updated periodically. The lists of approved technicians are updated weekly.

Backflow Prevention Forms

Frequently Asked Questions

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