What is a Cross Connection?

A cross connection is any connection between a customer's potable (drinking) water system and any source or system containing nonpotable water or other substances.  An example is a customer's potable water system being connected to a well, boiler/cooling system, or irrigation system.  These other systems are not potable water.

What is Backflow?

Backflow is the undesirable flow of nonpotable water or other substances through a cross connection and into the customer's drinking water system.  There are two types of backflow......backpressure and backsiphonage.  Backpressure is caused by water pressure in a customer's plumbing system being a higher pressure than water pressure in the public water main.  This can be created by pumps, temperature increases in boilers, etc.  Backsiphonage is caused by a negative pressure (partial vacuum) in the public water main.  The effect is similar to drinking water through a straw.  Backsiphonage can occur because of a water main break or by fire hydrant usage nearby.

Why does the Louisville Water Co. need to be concerned about cross connections?

Backflow into the public water system can pollute or contaminate the public water supply and make it unsafe to drink.  The Louisville Water Co. has the responsibility to provide water that is safe to drink under all circumstances.  For this reason LWC must take reasonable steps to protect its public water supply.

What is a Backflow Preventer?

A backflow preventer is a means or mechanism to prevent backflow.  It is a mechanical device that consists of two independent spring loaded check valves.  These check valves also are equipped with two shut-off valves and test openings.  The backflow preventer is usually located on the customer's main water where the water service enters the building.

Why do backflow preventers need to be tested annually?

Backflow preventers have internal springs, seals, and other moving parts that are subject to fouling, wear, or fatigue.  Because they are mechanical device they need to be tested and at times be serviced to ensure they are working properly.  The State Division of Plumbing, LWC service rules, and Metro Louisville Ordinance, requires the device to be tested annually.

If you have any questions regarding the Louisville Water Company Cross Connection Control program please call: John Ralston @ (502) 569-3657