Five Causes of Black Flow Issues in a Plumbing System

The plumbing pipes in your home are supposed to be a one-way street, and when things go awry with the flow of your plumbing it can pose a serious risk to the health of your home. Staying up to date on common plumbing problems like backflow issues is an important part of keeping up with your home maintenance — here’s what you should know about what causes backflow in pipes and how you can avoid it.

What is Backflow in Plumbing?

Backflow occurs when dirty or non-potable water flows backward into your clean plumbing supply. It can happen due to several reasons, including drops in water pressure, or a break in the main water supply line. Backflow preventers are commonly installed to prevent this from happening, but just like many other systems in your home, problems with installation and failing equipment can allow the issue to persist. Here are the four most common causes of backflow in plumbing:

Cross connections

Plumbing cross connections occur when a water supply line is connected to a non-potable source, such as a swimming pool or irrigation system. If the pressure in the non-potable source exceeds that of the potable water supply, the contaminated water can flow back into the home’s plumbing system.


This occurs when the pressure in the home’s plumbing system is greater than that of the public water supply. This can happen when there is a significant increase in demand for water, like the demand required for firefighters to smother a fire, or when a pump is used to boost water pressure in the home.


Backsiphonage is a negative pressure that is created in the home’s plumbing system, causing water to flow backwards. This can happen when a water main breaks or when water is shut off for repairs.

Sprinkler blowouts

Sprinkler blowout is another common cause of backflow. Sprinkler systems have their own water supply, and when they are blown out for the winter, water can flow backward into your plumbing system. To prevent this from happening, it’s essential to install a backflow preventer.

Improperly installed or maintained backflow prevention devices

Backflow prevention devices are designed to prevent backflow by allowing water to flow in only one direction. However, if backflow preventer installation is not done properly, or the equipment is not maintained, they can fail to function correctly. Common backflow preventer mistakes include installing a preventer without adequate space, a lack of regular preventative maintenance, and installing a backflow preventer that is incompatible with the associated plumbing system and/or local regulations.

Backflow Prevention & Testing in Hampton Roads Virginia

Backflow testing is essential to ensure the safety of your plumbing system. If you are looking for backflow testing near you, Worley’s is at your service. One of our experienced professional plumbers will inspect your plumbing system and test your backflow preventer to ensure that it’s working correctly. If there are any issues, we will make the necessary repairs or recommend the installation of a new backflow preventer.

Solve your plumbing backflow issues once and for all with one call to Worley’s Home Services! Call 757-356-4117 or contact us online.