KUB works hard to deliver safe drinking water. We need your help to be sure you don't accidentally endanger the public water supply through a cross-connection.

You can help by learning if you need a backflow device to prevent cross-connection. What are your responsibilities? This section will help answer questions, or you can see our Commonly Requested Documents for more.

Commonly Requested Documents

If you still have questions after reading this information, please call KUB's Cross-Connection Control Program at 594-8333.

What is a Cross-Connection?

Cross-connections are connections in your plumbing that could allow contaminated water from your home or business to flow backward if there is a loss of water pressure and enter the drinking water. You may introduce a risk of cross-connection if you directly attach something that uses chemicals or that could potentially add contaminants to the drinking water system to your water pipes, fixtures, or even to a hose. A direct connection to an alternative source of water, such as a well, spring, or harvested rainwater system, can also be a risk.

These are some common sources of cross-connections in homes:

  • Irrigation Systems
  • Swimming Pools and spas
  • Darkrooms
  • Water wells
  • Home fire-suppression systems 

Almost all businesses will need backflow protection. Click here for a complete listing of business categories that pose a risk for cross-connections and require a backflow prevention device.

Backflow Basics

What is a backflow device?

A backflow device is a special valve that prevents water from potentially flowing backward from your plumbing into the public water system.

You can also prevent backflow by keeping an air gap of at least two inches between the water source and anything that contains dangerous or objectionable materials. For example, don’t place your garden hose in the water of a pool you’re filling or in a bucket with soapy water or fertilizer. Leave space between the hose and the water in the pool or bucket.

What are my responsibilities if I may have a potential source of cross-connection?

If your water use introduces the potential for a cross-connection, you must install a backflow device following manufacturer’s instructions, local plumbing codes, and KUB specifications. You own this device and are responsible for maintaining and repairing the device as needed. Backflow devices must be tested annually, after installation, and after any repairs. KUB provides a list of state certified and KUB approved backflow testing companies. Companies on this list will send paperwork showing passing test results to KUB after each test. This paperwork is required after every test to ensure there is no disruption in your water service. KUB must terminate water service to customers who do not install, properly maintain, and test their device.

What do I need to know about installing a backflow device?

All potential risks identified by the Tennessee Department of Environment and Conservation (TDEC) and KUB’s Cross-Connection Control Program (CCCP) need a Reduced Pressure Zone device installed on the domestic water service line. The only exception is non-chemical fire suppression systems, on which you can use a Double Check device. KUB accepts only the installation of backflow devices approved by the USC’s Foundation for Cross-Connection Control and Hydraulic Research. A complete list of approved devices can be found on their website at www.usc.edu/dept/fccchr/list.html.

Depending on the type of water use, a licensed plumber, licensed fire line contractor, or state- certified backflow testing company may be able to install your device. Additional permits and inspections may be needed, so contact your local plumbing or building inspections office to determine their requirements. Backflow devices must be installed following manufacturer’s instructions, local plumbing codes, and KUB specifications.

How does KUB know if my device has been tested?

Devices must be tested annually by a state-certified and KUB- approved backflow tester. If you do not receive a notice from KUB to test your device, please call us immediately. Your backflow tester must submit test forms to KUB immediately after your device has been tested.

Test forms can be submitted by:

  • Mail to P.O. Box 59017, Mailstop JK15 CCCP, Knoxville, TN 37950
  • Fax to (865) 594-8316
  • E-mail to crossconnection@kub.org

Please direct all questions to the Cross-Connection Control hotline at (865) 594-8333.

Can I remove my backflow device?

Backflow devices can only be removed if an air gap is installed in its place, or if the use of water has changed so that the risk of cross-connection is eliminated. For example, if your device is installed outside on an irrigation system, you can remove the device if it has been tested and cap the water lines while the system is not in use. You cannot remove or bypass backflow devices and continue to connect potential risks to the water system. If in doubt, call KUB before removing your backflow device.

If my device is located outside, how do I keep it from freezing?

Backflow devices located on irrigation systems can be removed when not in use, which is typically in the colder months of the year. Winterizing your backflow device helps protect it from freezing or bursting, which can save you money on costly repairs. Here are some tips on winterizing an outdoor device.

  • Remove the backflow device before applying air pressure to winterize your irrigation system. Do not blow air through the backflow device or secondary water meter, as this may break internal parts.
  • Drain all the water from the device and store it in a location that stays dry and safe from freezing.
  • Put unions and caps on both inlet and outlet pipe for protection, easy removal, and easy reinstallation of the device.

For outdoor devices that must be installed year–round, you can protect the device by supplying a heat source or installing an enclosure or insulation to protect the device from freezing. Many local irrigation and backflow testing companies can advise on the best ways to protect your device from freezing.

What is a Portable Water Meter and when should it be used?

A portable water meter is a water meter that has a backflow prevention device permanently attached. The portable meter serves two purposes. First, it meters the amount of water used for billing purposes. Second, the backflow device provides protection to the public water supply.

Portable water meters must be used anytime water is obtained from a fire hydrant or non-metered structure. 

Common uses include filling up a swimming pool, car–wash fundraisers, or business- related uses, such as at construction sites. There is a fee to obtain a portable meter. Please call 524-2911 for more information.

The TDEC Division of Water Supply requires all water utilities to have an approved Cross-Connection Program. KUB is a member of the American Backflow Prevention Association (ABPA). Here is a video created by the ABPA on the importance of backflow preventers and cross-connection control.