The water that runs through the pipes of the HCWSA distribution system is meant to run in one direction. When water attempts to run in the opposite direction in the system, it is called backflow. There are two conditions that can cause backflow. It may occur due to either backsiphonage or backpressure in the water system.
- Backsiphonage can occur when a water main or plumbing system in a building loses water pressure, thus creating a reduced pressure in the water supply piping. This reduced pressure will allow the direction of the water in the system to flow opposite of the normal direction of flow. Such pressure differences can cause siphoning of non-potable water and other liquids back into the potable water lines.
- Backpressure occurs when water pressure in a building or fixture becomes greater than the water pressure in the water supply piping. This condition can force non-potable water or other fluids back into the potable water system.
Backflow can take place within any water distribution system whether it is private or public. Backflow can be one of the greatest threats to the safety and integrity of a local water system. For that reason, HCWSA has implemented a Backflow Prevention Program to ensure the prevention of potentially hazardous cross-connections (any actual or potential connection between the public water supply and a source of contamination or pollution) to the public water system.
HCWSA requires all commercial and/or industrial facilities to have an approved backflow prevention device installed. All homes constructed after 2001 should also have backflow prevention devices. Additionally, whenever HCWSA rehabs older water lines in a subdivision, backflow prevention devices are installed.
While protecting a public drinking water system from potential backflow, these devices also seal water off inside a customer's home. As a result, a backflow prevention device could create higher pressure on an existing plumbing system (both on the hot water and cold water side).
For some homeowners, a spike in pressure also could set off the relief valve on hot water heaters or cause other damage to the plumbing system and/or the house. Thus, customers should check to make sure pressure relief or thermal expansion devices are installed and operating properly on or within their plumbing systems.
As a result of a change in the plumbing code in 2001, all homes built since that time are required to have such thermal expansion devices included in their construction. However, homes built prior to 2001 may not have these capabilities inside the house. Customers should consult a certified plumber if they have any doubts about their plumbing's condition. The HCWSA will not be responsible for any plumbing problems that may arise as a result of non-existing or improperly installed thermal expansion or pressure relief equipment.
The HCWSA program conforms to the Georgia Rules for Safe Drinking Water, which requires suppliers of public water to implement a Backflow Prevention Program that will ensure the prevention of potentially hazardous material contaminating the public water system through cross-connections.
For further information on backflow prevention, customers may call us at (678) 583-4500. Click here to contact us via e-mail to address concerns with the program.
Commercial and industrial facilities are required to have their backflow prevention devices tested periodically by someone who is certified to do so by HCWSA. A Backflow Prevention Report must be submitted to the Industrial Monitoring Department of HCWSA at the conclusion of the test.
Below are links to various types of Thermal Expansion Devices commonly used in homes:
- Toilet Thermal Expansion Relief Valve
- Potable Water Expansion Tanks
- Combination Ball and Relief Valve
- Calibrated Pressure Relief Valves
Devices can be found at most hardware stores. They are made from a variety of manufacturers including:
For additional information on backflow prevention and thermal expansion, please refer to the following documents: