Cobb County Expansion Tank Requirement

Cobb County Expansion Tank Requirement

Cobb county has joined the ranks of many other Metro-Atlanta water companies by improving the infrastructure of our water systems. Many Cobb residents have been receiving letters from Cobb County Water Department informing them that they will be installing new back flow prevention devices in their area. The letter further recommends that all residents bring their homes up to present code by installing a thermal expansion device to create a closed system. The thermal expansion tank is a simple and efficient method to ensure that your system is safe.

What is Thermal Expansion?

Thermal expansion refers to the characteristics of water to expand when heated, and to contract when cooled. Unlike air, which can be compressed, water grows in volume and must be accommodated when heated.

Why is Thermal Expansion occurring?

In a water heater, thermal expansion can create more pressure than the system can handle. When unchecked, this pressure can result in expensive leaks, as well as damage to the water heater, pipes or other plumbing fixtures.

When is a Thermal Expansion device necessary?

An expansion control device is required by section 607.3.2 of the Standard Plumbing Code and is necessary when any of the following occur:

  • A recent water meter replacement
  • A water heater replacement
  • The construction of a new home
  • When a back flow prevention device has been installed on the water meter or a new pressure reducing valve is installed on the service line

Still have questions? Contact one of our friendly office staff and we will be glad to assist you in determining if you need to install or replace your existing thermal expansion tank.