What is Cross Connection/Backflow Prevention?

The words “cross connection” may not mean much to most, but to the employees of the City Water Department, especially Water Quality Control Specialists, the words mean trouble. What is cross connection? Simply put, cross connection occurs when contaminated water, potentially hazardous gas or liquid, gains entrance to and pollutes a safe water supply. Through the careful monitoring of the city water supply system and the installation of backflow prevention assemblies, the risk of cross connection can dramatically be reduced.

A backflow prevention assembly prevents potentially dangerous substances or contaminated water from entering the public water supply. This assembly consists of a valve that allows water to enter a building but prevents the water from returning to the supply line. Cross connection contamination usually occurs when there is a loss of pressure in the city system. The loss of pressure from a main line break, a pumper fire truck, etc, can create a back-siphonage situation that will actually pull the water from a building/residence back into the water supply system.

In 1996, the City implemented a BMA approved Cross Connection Control ordinance 4296. The State Division of Water Quality requires that all public water systems maintain an active program to identify and control cross connections. This ordinance is the basis for the city’s program. Everyone that installs or repairs these assemblies is required to be certified by the State of Tennessee.

There are 10 city employees certified for cross connection and backflow prevention installation and repair. To date, the city has had 1200 backflow prevention assemblies installed and are maintained by city staff.

Other parts of the city’s Cross Connection Program are Surveying, and Public Education and Awareness. Surveying the Water System for existing or potential cross connections, and effectively eliminating them is crucial to ensuring Safe, Uncontaminated Drinking Water for Everyone!

For information on how you can help prevent backflow related to cross connection –  Cross Connection Education Sheet.

We further encourage residential customers to print out the survey below and either mail it to us or drop it off at the Customer Service Center or the Water Maintenance Building at 1113 Konnarock Road.

Residential Cross Connection Survey

Commercial and Industrial customers, or residential customers who would like to schedule an on-site inspection for the detection and elimination of Cross Connections, are encouraged to contact a Water Quality Control Specialist @ (423) 229-9454.

Click on the file below to view the city’s policy for Backflow Prevention Requirements.

** Please call before installing any home water treatment system or device. The addition of these home-treatment systems may classify as ‘Post-Treatment’ and a Backflow Prevention Assembly may be required.

Backflow Prevention Requirements Part 1 Part 2 Part 3 – Requirements, Surveying, Existing Connections

Inside Fire Line Installation Inside Parallel System Inside RP Model

Outside Fire Line Installation Outside Parallel System Outside RPZ Installation

Certified Contractors List – List of Contractors certified by the State of Tennessee as Competent in the installation of Backflow Prevention Assemblies

For more information please call the Water Technical Services Division – (423) 229-9454.

Approved Backflow Prevention Assemblies – Revised January 30, 2020

Only assemblies currently approved for containment by the USC Foundation for Cross-Connection Control and Hydraulic Research are to be used for the protection of Public Water Systems against backflow hazards. For information on any assemblies that may have been approved since the printing of this list, please call the Division of Water Supply at (615) 532-0164 or the Fleming Training Center at (615)898-8090.

Unless otherwise specified by the manufacturer all assemblies are to be installed on cold potable water applications – below 110 F. Also all Double Check Valve Assemblies, Reduced Pressure Principle Assemblies, Double Check Detector Assemblies, and Reduced Pressure Principle Detector Assemblies are Approved for HORIZONTAL ORIENTATION ONLY, unless specifically noted. Use of spare parts other than those of the original manufacturer invalidates the Approval. The following are lists of Approved assemblies by manufacturer.

Double Check Valve Assemblies

Double Check Valve Detector Assemblies

Reduced Pressure Principle Detector Assemblies & Reduced Pressure Principle Assemblies

Thermal Expansion – What is it? And How Should I Control It?

Thermal Expansion Information

Classes Offered for Blackflow Prevention Testing and Evaluation

The City of Kingsport hosts classes for Backflow Prevention Testing and Evaluation in partnership with the State’s Fleming Training Center and TAUD. These classes are extremely beneficial to contractors, businesses, or anyone that would prefer to work on and test these devices in-house, or would like to broaden their knowledge base. Classes are held at the Civic Auditorium in early spring and again in the fall. TAUD conducts our spring classes, and Fleming Training Center conducts our fall classes. Graduates from these classes will receive a State Certificate of Competency for Testing and Evaluation of Backflow Prevention Assemblies. For more information on either of these classes, please call (423) 229-9454 and ask to speak to one of our Water Quality Control Specialists, or visit http://taud.org (TAUD) or http://www.tn.gov/environment/water/fleming.shtml (Fleming Training Center)