What is Backflow and How Does It Affect Water Quality?

While the City of Southlake consistently invests in and maintains quality infrastructure, it is always important to understand how systems work and how you can help us keep Southlake special.

Backflow is a term that describes water flowing in the opposite way from its intended direction, either from a decrease in pressure in the drinking water supply lines or increase of pressure on the customer’s side. The biggest issue that backflow can potentially cause is water contamination, if the proper backflow prevention assemblies aren’t installed and maintained on your plumbing system.

Water is designed to flow towards the point of lowest pressure, therefore if a water main were to break or a surge of fire hydrants were opened to fight a fire, the pressure would drop, forcing the water to flow backwards and potentially carry contaminants into the waterlines. If there is an illegal cross-connection to a source of contamination, which is when a physical connection between the drinking water supply and a possible source of contamination or pollution collide, it could result in the water being unsafe to drink. The most frequent types of cross connections include a water hose in a pool or soapy bucket, water wells connected to irrigation systems, coffee makers and ice machines with direct water lines, and chemical injection units at restaurants.

The good news is that backflow can be prevented by utilizing the proper backflow prevention assembly or an air gap, which is a physical separation between the end of the water supply pipeline and the flood level of the fixture in question. A good example of an air gap is the distance between the bottom of your sink tap and the height of your sink bowl.

The City of Southlake conducts customer service inspections to analyze and remove current or potential cross connections on a consistent basis throughout the year. If you have recently received a letter from the City stating an assembly has not been tested in the last year and are unsure of your records, you can search search here for the last backflow test or call 817-748-8082 to update your file.

If you are a licensed Backflow Prevention Assembly Tester and you’re interested in becoming a registered to test in the City of Southlake, the City has partnered with VEPO LLC for an online database and documentation of backflow prevention and tester registration. Learn more about the process here.