Back Flow and Cross Connection Prevention

What is Backflow Prevention and Cross Connection?

Click HERE to access the survey if you're unsure if you could have a potential cross-connection. 

What is a cross-connection?
Any physical connection created between a possible source of contamination and any drinking water system piping. 

What is backflow?
It is the flow through a cross-connection from a possible source of contamination back into the drinking water system. It occurs when a cross-connection is created and a pressure reversal, either as backsiphonage or backpressure, occurs in the water supply piping. 

Why be concerned? 

What causes back-siphonage?
Back-siphonage occurs when there is a loss of pressure in a piping system. This can occur if the water supply pressure is lost or falls to a level lower than the source of contamination. This condition, which is similar to drinking from a glass with a straw, allows liquids to be siphoned back into the distribution system. 

What causes backpressure?
Backpressure occurs when a higher opposing pressure is applied against the public water system’s pressure. This condition allows undesirable gases or liquids from another system to enter the drinking water supply. Any pumping system (such as a well pump) or pressurized system (such as steam or hot water boilers) can exert backpressure when cross-connected with the public water system. 

What can I do? 

What must be done to protect the public water system?
The public water supplier must determine potential and actual hazards. If a hazard exists at a customer’s public water supply service connection, the customer will be required to install and maintain an appropriate backflow preventer* at the meter and/or at the source of the hazard. 

*Check with your water supplier to verify which backflow preventer is required before purchase or installation. 

Who is responsible?
In Ohio, the responsibility for preventing backflow is divided. In general, state and local plumbing inspectors have authority over plumbing systems within buildings, while Ohio EPA and water suppliers regulate the protection of the distribution system at each service connection. Water customers have the ultimate responsibility for properly maintaining their plumbing systems. It is the homeowner’s or other customer’s responsibility to ensure that cross-connections are not created and that any required backflow preventers are tested yearly and are in operable condition. 

What is the law?
Ohio Administrative Code Chapter 3745-95 requires the public water supplier to protect the public water system from cross-connections and prevent backflow situations. The public water supplier (our water District) must conduct cross-connection control inspections of their water customers’ property to evaluate hazards. 

What are some common backflow hazards that threaten the homeowner and other consumers?

What are examples of cross-connection and backflow scenarios?

Information on this page has been developed from the Ohio EPA's website at