Cross Connection Program FAQ

What Is Cross Connection?

Cross-Connection – any actual or potential connection between potable (drinkable) and non-potable (not drinkable) water.

What Is Backflow?

Backflow is the undesirable reversal of flow of non-potable water or other substances through a cross-connection and into the piping of a public water system or consumer’s potable water system. There are two types of backflow–backpressure and back-siphonage.

What Is Backpressure?

Backpressure is any condition where the customer’s internal water pressure becomes greater than the pressure supplied by the city, which pushes water opposite of the intended direction of flow.

Backpressure can be created within a customer’s facility by pumps, heating and cooling systems, etc.

What Is Back-Siphonage?

Back-siphonage is any condition where there is a sudden decrease in city water pressure, which pulls water from the customers facility.

This back-siphonage suction effect is similar to drinking water through a straw and can be created within the city’s water distribution system by water line flushing, fire fighting, or water main breaks.

Why Be Concerned About Backflow?

An unprotected cross-connection (commercial, residential, irrigation) can allow contaminates from customer’s internal plumbing/piping system into the city water supply, effecting the health and safety of the drinking water.

Potential contaminates include anti-freeze, herbicides, pesticides, caustic or acidic compounds and can result in disease, illness, injury, or even death.

Customers of the Louisville Water Company can be a valuable resource in identifying and eliminating potential cross-connections.

Types of Protection

When a cross-connection has been identified and can not be eliminated, a LWC approved backflow prevention assembly must be installed that is appropriate for the hazard.

Containment vs. Isolation?

A containment backflow prevention device protects the public water supply from any hazards in a customer’s plumbing/piping system. This containment device will be located on the customer’s incoming service line before any branch plumbing.

An isolation backflow prevention device protects a facility’s internal water supply from an identified cross-connection hazard located within that facility.  This isolation device will be located at the identified hazard.

A containment device contains contaminants within a building and an isolation device contains contaminants to a specific area within a building.


Air Gap Separation – a method of preventing backflow through the use of an unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a plumbing device or fixture, tank or other device and the flood level rim of the receptacle.

Atmospheric Vacuum Breaker – an approved backflow device used to prevent back siphonage that is not designed for use under static line pressure.

Back Pressure – pressure created which causes water or other liquids to flow or move in the opposite direction of that which is desired.

Back Siphonage – backflow which is due to reduced or sub-atmospheric pressure within a water system.

Backflow – the flow of water or other liquids into distribution pipes of a potable water supply from any source other than the intended source.

Backflow Preventer with Atmospheric Vent – a device which has (2) independently operating check valves separated by an intermediate chamber with a means for automatic venting into the atmosphere, in which the check valves are force loaded to a normally closed position and the venting means is force loaded to a normally open position.

Backflow Prevention Device (approved) – a method used to prevent backflow that has been approved by LWC, EPA and KYDOW.

Backflow Prevention Device Tester (certified) – the individual who holds a certificate for the testing of backflow preventer in the Commonwealth of Kentucky.

Containment Device- A backflow device on the incoming line or service connected to the main public water supply.

Double Check Valve Assembly – a backflow prevention device that incorporates an assembly of check valves, with shut-off valves at each end and appurtenances for testing.

Inspection – a survey by a qualified individual to determine the existence and location of cross connections and / or the physical examination and testing of an installed backflow prevention device to verify that the backflow prevention device is functioning properly.

Isolation Device- A backflow preventive device installed after the meter and to individual branches of a plumbing service with a building..

Potable Water– Water from any source passing all test requirements and has been approved by the Environmental Protection Agency (E.P.A.) and the KY Department of Water (KYDOW) for safe human consumption.

Pressure Vacuum Breaker – an approved backflow prevention device designed to prevent only back siphonage and which is designed for use under static line pressure.

Reduced Pressure Vacuum Preventer – an approved backflow prevention device that incorporates:

  • two (2) spring loaded check valves
  • an automatically operating differential relief valve located between (2) check valves
  • two (2) shut-off valves
  • necessary appurtenances for testing; and which is designed to operate so that:
    • The pressure in the zone between the two (2) check valves is maintained at a value less than the pressure on the public water system side of the device, and
    • At cessation of normal flow, the pressure in the zone between the two (2) check valves is maintained at a value less than the pressure on the public water system side of the device, and
    • In the case of leakage of either check valve, the differential relief valve shall operate to maintain reduced pressure in the zone discharging to the atmosphere.

Unapproved Source – the source or distribution system for any water or other liquid which has not been approved by the EPA or KYDOW as being safe or sanitary for human consumption, including but not limited to any waste pipe, soil pipe, sewer, drain, or non-acceptable potable water system material.

Potential Cross-Connection Hazards

Examples of common sources of cross connection hazards are listed below (this is not intended to be a complete list):

  • Boilers
  • Chemical / Cleaning Mixing Stations
  • Chillers
  • Cooling Towers
  • Dishwashers (industrial)
  • Firefighting Systems – including sprinklers and standpipes
  • Heat Exchangers
  • Hose bibs connected to non-potable sources
  • Industrial Fluid Systems – those that contain cutting and hydraulic fluids, coolants and other similar types of contaminants.
  • Irrigation Systems
  • Laboratories
  • Laundries
  • Multi-story buildings (three stories or greater)
  • Photography Studios
  • Priming Lines – including air conditioning pumps, booster pumps, sewer pumps
  • Refrigeration Units
  • Steam Generating Facilities
  • Swimming Pools

Louisville Water Company Cross Connection Program Details

The Louisville Water Company has implemented a cross-connection control program as required by federal, state and local regulations to prevent potential backflow contamination.

Louisville Water Company Responsibilities

  • The administration of a cross-connection control program. This includes inspections of industrial, commercial, fire, irrigation, and domestic customer service lines for identification and assured containment of potential hazards.
  • Specifically, our inspections check for the following:
    • If a potential cross-connection hazard exists
    • If a backflow preventer is needed based on a risk assessment score
    • If an installed backflow preventer matches LWC records and has had an annual test performed
    • Internal customer plumbing meets KY Division of Plumbing code and isolates identified cross-connection hazards.

Customer Responsibilities:

  • Allow access to Louisville Water Company inspectors upon request.
  • Initial installation, testing, and submission of test results by a certified technician to Louisville Water Company Cross-Connection Control office for all containment backflow prevention devices.
  • Annual testing and submission of test results by a certified technician to Louisville Water Company Cross-Connection Control office for all containment backflow prevention devices.

**It is recommended that all customers retain annual test records for all containment and isolation devices on their premises to be available upon request by any LWC, KYDOW, EPA, or Plumbing Inspector for review or in cases of emergency.

**It is recommended that customers install isolation devices when needed to protect themselves from potential internal risks and hazards located within their plumbing system.

**If you are an industrial or commercial customer (including multi-family), you will notice an assessment fee called the Cross Connection Control Fee on your statement. This monthly fee supplements the Cross Connection Control Program.

Certified Backflow Preventer Tester’s Responsibilities:

  • Having a backflow preventer test kit that is maintained in proper working order and calibrated when necessary.
  • Any backflow prevention device that fails testing must be repaired and retested.
  • Recording the results for each passing inspection on test report forms approved by Louisville Water Company.
  • Submitting copies of passing backflow device test reports within 10 days to the Louisville Water Company Cross-Connection Control office via email, fax or mail.

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