Cross Connection and Backflow Prevention

The goal of Tennessee American Water is to provide drinking water which meets or is better than the State and Federal drinking water standards to each of our customers. Plumbing connections are made to a public water distribution system for the purpose of providing drinking water to the customer.  Due to conditions in a customer’s private plumbing the possibility of a backflow incident could potentially compromise the drinking water supply.  Cross connections may result in substances being forced into the public water system that could, if permitted, be responsible for transmitting disease-causing organisms, toxic materials, or other hazardous substances to customers that may adversely affect large numbers of people.  Tennessee American Water has been and will continue to be vigilant in enforcement of an effective cross-connection program to comprehensively inspect and protect the drinking water system.

Authority for Cross Connection Control

Tennessee American Water’s policyexpresses clear intent that the distribution system is to be operated free of cross-connections which could endanger the health and safety of our customers who have come to depend upon the public water supply. The cross-connection policy is considered to be a sound basis for the control of cross-connection hazards by the operating staff and management of Tennessee American Water. The provisions contained within this policy provide legal authority in keeping with the requirements set forth in Section 68-221-711 (6) of Tennessee Code Annotated and Section 1200-5-1-.17(6) of Tennessee Department of Environment and Conservation Rules governing Public Water Systems, as well as the provisions in the company’s tariff.

What is a Cross Connection and Backflow?

Plumbing cross connections are actual or potential connections between a potable and non-potable or unapproved water supply and constitute a significant public health hazard.  These cross connections are controlled by the use of testable backflow devices.   All Tennessee American Water customers with an unapproved connection are required to take steps to prevent cross connections and backflow to the public water system. This includes the installation of an approved backflow prevention device and having it tested on an annual basis.

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

Backpressure happens when the pressure of the customer’s private water line exceeds the pressure in the public water distribution main. An example is 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 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 i similar in effect to the sipping of water through a straw. Negative pressure in the drinking water distribution system may happen due to a water main break or when a hydrant is being used. 

How to Prevent Backflow Contamination 

Backflow contamination can be prevented.  All non-residential water utility customers are required to have approved and functioning backflow-prevention devices installed and test on an annual basis.   In some cases, residential customers may also be required to install backflow prevention devices.  Installation of backflow prevention devices can be completed by an independent plumbing contractor. The cost of the device, installation, maintenance and testing is the responsibility of the customer. We recommend that customers obtain cost estimates from approved contractors before any work is done. 

It is required by the State of Tennessee and Tennessee American Water that these devices pass an annual test.  These tests must be performed by testers that are certified by the State of Tennessee.  For a list of certified testers please see the link below.

Commonly Asked Q and A

List of Certified Backflow Testers

Backflow Installation Report

Customer Plumbing Survey

Blank Test Form