Backflow is a term in plumbing that refers to when the water system has an undesirable reversal of flow by backpressure or backsiphonage. When backflow happens, homeowners can get contaminated water into their homes, which puts themselves and their family members at risk. To prevent backflow from happening, laws and codes require a series of backflow prevention measures.

Backpressure: Your water’s flow can reverse when the water pressure downstream exceeds the pressure in the water supply system. This can occur in unvented heating systems, as thermal expansion increases pressure. Other pressurized systems like pumps, elevated tanks, and boilers that are designed to drive water to higher floors can have backflow problems.

Backsiphonage: Backsiphonage occurs when water pressure drops dramatically because of sudden overuse or withdrawal rate, which can also cause backflow issues. This occur when a supply is interrupted or drained down. Backsiphonage is a common occurrence in broken watermain, during fire-fighting emergencies, or other civic drainage jobs that necessitate excess water use in a short amount of time.

When backflow occurs, the new, clean water becomes blended with dirty, used water. This leads to the pollution of your potable drinking source. Some tell-tale signs of backflow include noticeable changes in the taste, smell, and color of your water. When you take a closer look at backflow, elements that are supposed to be distributed away from your home may be mixed in, including:

• Fertilizers
• Human/Pet waste
• Pesticides
• Chlorine from pools/spas and other chemicals
• Shampoos, soaps, and other household cleansers from dishwasher/sinks/showers