A backflow preventer is a device that’s installed on your home’s water pipes that allows water to flow in one direction but never in the opposite direction. Its sole job is to prevent drinking water from being contaminated due to backflow. When water enters your home from the main water supply line, it should only ever flow in one direction. But sometimes water can actually flow backwards and seep back into the main water supply line. And when this happens, backflow can contaminate the public drinking supply with: Fertilizers/pesticides, Human waste, Chlorine from pools/spas, Soap from sinks/dishwashers/showers

And that’s where a backflow prevention system comes in handy. Because backflow-prevention assemblies are mechanical assemblies that can fail, the TCEQ requires testing of all backflow-prevention assemblies at installation by a TCEQ-licensed tester. Backflow-prevention assemblies installed to protect against any health hazard must be tested annually.