Frequently Asked Questions

What is a Cross-Connection?

  • A cross-connection is a physical connection between a possible source of contamination and the public drinking water system. This connection, if not properly protected, can lead to the contamination of the drinking water system through a backflow event. Any service connection is a cross-connection.
  • What is backflow?
  • Backflow is the reversal of water flow through a cross-connection from a possible source of contamination into the public drinking water system. Backflow may be caused by either backpressure or backsiphonage. A loss of pressure in the public drinking water system may lead to backsiphonage through unprotected cross-connections, or backpressure may be created when the water pressure of a facility’s internal water system is elevated above the supply pressure of the public drinking water system resulting in backflow through unprotected cross-connections
  • What are backpressure and backsiphonage?
  • Backsiphonage occurs when the pressure in the public water distribution system (water mains) drops below atmospheric pressure and creates a partial vacuum, which could “siphon” contaminants back into the potable (drinking) water system. Backpressure occurs when downstream pressure (from within a home or business) is greater than the water pressure supplied by the public water system.


  • What is a backflow prevention device?
  • A backflow prevention device is a means or mechanism to prevent backflow. The basic mechanism for preventing backflow is a mechanical backflow preventer, which provides a physical barrier to backflow. The principal types of mechanical backflow preventers are the reduced-pressure principle assembly, the pressure vacuum breaker assembly, and the double check valve assembly. Backflow prevention devices will only allow flow to occur into your home or business and, if operating properly, will never allow flow in the opposite direction (toward the water main).
  • What is a Cross-Connection Control Program?
  • The purpose of a Cross-Connection Control Program is to protect the public potable water supply from the possibility of contamination or pollution by requiring the installation and annual testing of backflow prevention devices.
  • Who gives the authority to implement the program?
  • Authority to enforce Cross-Connection Control regulations comes from Pennsylvania’s Safe Drinking Water Act, the Pennsylvania Code Chapter 109, the Pennsylvania Department of Environmental Protection, and the International Plumbing Code Section 312.
  • How often does backflow really occur and how much damage can it cause?
  • Backflow occurs very often, with potentially lethal outcomes. There are numerous documented cases where death and serious injury have been caused by backflow. EPA has stated that there have been nearly 10,000 documented cases of illness caused by contaminants that were introduced by backflow into potable water systems. Financial loss due to equipment damage and lawsuits has ranged into the tens of millions
  • What kind of backflow device do I need?
  • The type of backflow device depends upon the degree of hazard present at your location. The degree of hazard depends on the use of water at your location and what could potentially enter the system. Generally, a higher degree of hazard requires a Reduced Pressure Zone (RP) Assembly, and a lower degree of hazard requires a Double Check (DC) Assembly. If you have any questions regarding the type of device required at your site, please contact the Cross-Connection Control Department at 844-605-5213.
  • Who should install and test a backflow device?
  • While there are no standards set for who can install a backflow prevention device, repairs and tests to backflow preventers must be performed by certified technicians. Technicians testing backflow preventers should be American Society of Sanitary Engineering (ASSE) Series #5110 certified. Technicians repairing backflow preventers should be ASSE        Series #5130 certified. Please contact your local township which may have additional requirements on who can install a backflow.
  • What can you do to prevent backflow situations in your home or business?
  • • Be aware of and eliminate and/or protect cross-connections.
  • • 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 outside faucets)
  • • Install approved backflow prevention devices on lawn irrigation systems and on fire sprinkler system services.
  • • Do not create a connection between an auxiliary water system (well, cistern, body of water) and the water supply plumbing.