Backflow Prevention & Cross-Connections

A backflow prevention device is a fixture installed on a private water service line that prevents the reverse flow of water from a building into the public water system. A properly installed device will prevent cross-connection contaminants from entering the water system.

The device is to be tested every twelve months at a minimum. An ASSE Certified Tester must submit the results through our Backflow Test Submission Portal. When creating an account, testers must upload a digital copy of their ASSE Certification and Calibration Certificate for each backflow test device. 

Common backflow prevention devices include:

  • Double Check Detector Assembly (DCDA) typically installed on fire line
  • Reduced Pressure Zone Assembly (RPZ) typically installed on domestic water service line


A cross-connection is described in plumbing code as any physical connection or arrangement between two otherwise separate piping systems, one of which contains potable water and the other either water of unknown or questionable safety, whereby there exists the possibility for flow from one system to the other.

Examples of common commercial cross-connections are:

  • Carbonator for soda machine
  • Coffee and/or tea brewers
  • Chemical Dispensers
  • Boilers


Building owners must ensure that contaminated water from building systems does not enter waterlines and negatively affect the health and safety of those who use the water supply. Undetected contaminants can cause illness or death. PWSA includes backflow regulations in the PWSA Water Tariff Part III Section B, Construction and Maintenance of Facilities.

The Allegheny County Health Department Plumbing Code Chapter 860 and the Pennsylvania Department of Environmental Protection Title 25 Pennsylvania Code, Section 109.709 also address standards and regulations for installing and testing a backflow prevention device.

When installing a new device, a certified plumber must get a plumbing permit and inspection from ACHD. Test results must be forwarded to PWSA annually after installation, repairs, or replacement. It is the customer’s responsibility to notify PWSA of any new, repaired, replaced, or removed devices. If you do not comply, you are subject to water shut off.

Frequently Asked Questions

How often do I need to test my device?

The backflow prevention device is required to be tested every twelve (12) months, at a minimum, by an ASSE Certified Tester. PWSA will send an email notifying the property owner of the testing result due dates. If you do not receive an email from PWSA, you are still required to hire a tester to submit your results to our cross-connection prevention department.

Do I need to notify PWSA if I repair my backflow prevention device?

Yes; devices must be tested after repairs are made. Results of the testing must be submitted to PWSA by an ASSE Certified Tester using our backflow test submission portal.

How do I submit my backflow test documentation?

As a commercial property owner, you must hire an ASSE Certified Tester. Your tester will submit the test result through our backflow test submission portal. You will receive an email notification when PWSA approves the test result submission.

Where do I find an ASSE Certified Plumber?

ASSE is an organization that sets standards plumbing products and practices. Many jurisdictions require this certification before performing backflow testing. You can search for a certified professional by visiting ASSE’s website.

How does a certified tester submit test results to PWSA?

A certified tester must sign up for an account in our backflow test submission portal. When first signing up for an account, a digital copy of the backflow prevention assembly inspector/tester certification card, certification number, and calibration certificate for each differential pressure gauge or other backflow test equipment will be required.

How do I get in touch with the PWSA Cross-Connection Compliance team?