The Commonwealth of Pennsylvania regulations require all public water systems to implement a cross-connection control program. Cross-connections are the physical connections between the water system and potential contaminant sources, such as irrigation systems, fire protections systems, and any other potential or actual hazard connected directly to the main water supply. “Backflow” is the reverse flow from the fixture/equipment back into the water system piping. Without being properly protected, if a backflow event were to occur, contaminants could flow back into the public water supply.

Consequently, it is necessary for Pennsylvania American Water to establish and maintain a cross-connection control program to help ensure cross-connections are protected and backflow preventers are tested annually.

To administer this program, Pennsylvania American Water has partnered with Backflow Solutions, Inc. or BSI Online, the nation’s leading backflow data management firm. BSI is fully devoted to helping public water systems with the development, implementation, and maintenance of cross-connection control programs. Inquiries regarding your testable backflow device should be directed to BSI Online at 888-966-6050 or All inquiries regarding non-testable devices should be forwarded to 1-877-290-1769 or

Please check your test/inspect letter to verify if you have a testable or non-testable device. Non-testable devices are listed as Residential Dual Checks (RDC) and need to be either inspected, repaired, or replaced every five years. All other devices are testable and require testing reported annually through BSI Online.

What is Cross Connection?

Cross Connection is any actual or physical connection between a potable (drinkable) water supply and any source of non-potable liquid, solid or gas that could contaminate drinking water under certain circumstances. Learn more in our Cross Connection fact sheet.

What is Backflow?

Backflow is the reverse flow of water or other substances into the treated drinking water distribution system. There are two types of backflow: backpressure and backsiphonage.

  • Backpressure happens when the pressure of the contaminant source exceeds the positive pressure in the water distribution main. An example would be when a drinking water supply main has a connection to a hot water boiler system that is not protected by an approved and functioning backflow preventer. If pressure in the boiler system increases to where it exceeds the pressure in the water distribution system, backflow from the boiler to the drinking water supply system may occur.  
  • Backsiphonage is caused by a negative pressure (vacuum or partial vacuum) in the water distribution system. This situation is similar in effect to the sipping of water through a straw. In the drinking water distribution system, negative pressure (backsiphonage) occurs during a water main break or when a hydrant is used for fire fighting.

Why should you be concerned?

Backflow may affect the quality of the drinking water at your home, business or facility and has the potential to create health hazards if contaminated water enters your water supply plumbing system and is used for drinking, cooking or bathing. Backflow events occur more often than you might think although most do not create health hazards. Unprotected cross-connections with water supply plumbing or public drinking water piping systems are prohibited. We are all responsible for protecting our water supply from backflow that may contaminate our drinking water. It includes complying with the plumbing code and avoiding unprotected cross connections.

Who is responsible?

The responsibility for preventing backflow is divided. In general, state and local plumbing inspectors have authority over plumbing systems within buildings while state regulatory agencies and public water suppliers regulate protection of the distribution system at each service connection. Water customers have the ultimate responsibility for properly maintaining their plumbing systems. It is the water customer’s responsibility to ensure that unprotected cross-connections are not created and that any required backflow prevention devices are tested in accordance with state requirements and maintained in operable condition.

Preventing backflow situations in your home and business

  • Be aware of cross connections, eliminate or isolate them
  • Maintain air gaps on sinks and when using hoses.
  • Do not submerge hoses or place them where they could become submerged.
  • Use hose bib vacuum breakers on fixtures (hose connections in the basement, laundry room, and on outside faucets/spigots).
  • Install approved backflow prevention devices on lawn irrigation systems and on fire sprinkler system services. Types of preventative required devices are determined based on the potential type of pollutants or contaminants high, low or moderate. In low hazard situations, the installation of a residential dual-check device might be allowed.

If you have any questions regarding your backflow device and/or testing, please call BSI Online at 888-966-6050 or email  Failure to comply can result in water service disconnection after repeated request from BSI Online. If your letter is regarding water service disconnection, please call our Cross Connection Hotline at 1-877-290-1769.


We will work with you to answer any questions you may have regarding backflow prevention and the corrective actions necessary to ensure compliance. Below are additional resources that may be helpful.

Residential Customers

If you have an expansion tank installed on your home plumbing, please view our FAQs and video on how you can prevent billing inaccuracies and backflow.

Survey for non-residential customers: Complete our survey and fax it back to us. We will help determine whether you are in compliance with cross-connection/backflow prevention regulations.