A physical connection between potable water and an actual or potential contamination hazard that could make the water unsafe to drink. Wherever there is a cross-connection, there is a potential threat to public health from contaminants.

Water flowing in the opposite of its intended direction, either from a loss of pressure in the supply lines or an increase in pressure on the customer’s side. When the water backflows it can carry contaminants with it into the water lines.

Garden Hose: Backflow can occur at your home if you leave a garden hose turned on and submerged in a swimming pool, inserted it into your car’s radiator to flush out the antifreeze, or attached it to an insecticide sprayer. That material could siphon back into your potable water. Private well: Backflow can also occur from an untreated water supply, such as a private well, if the well plumbing is connected to the potable-water-supply plumbing. The untreated water could be pumped into the potable-water supply serving your home and into the public water system. Lawn Sprinkler System: TCEQ regulations require that all lawn sprinkler systems be protected through a backflow-prevention assembly - without which, the stagnant water and anything in it, from the sprinkler system could be drawn into the potable water supply for your home.

Backflow into a potable-water system can be prevented by using a backflow-prevention assembly , or an air gap, which is a physical separation between the water supply and a potential source of pollution. Licensed professionals as well as your public water purveyor are responsible for determining the type of backflow-prevention assembly required, based on the degree of hazard.

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.

How Cross Connection and Backflow Can Lead to Contaminated Water Here is one example of how... While mixing a batch of pesticide, a worker pushed a garden hose into the tank until it touched the bottom. Nearby, city utility workers opened a flush valve, releasing a large flow of water from a water main. Where the worker was mixing the pesticide, the water pressure dropped, and the flow in the hose reversed. Water and pesticides flowed from the pesticide tank back through the hose and into the water lines of the residence. Luckily, this is where it stopped: The worker mixing the pesticide realized the danger and alerted the utility workers, who closed the flush valve before the contamination reached the city’s distribution line. Still, good water and time were wasted: To remove the pesticide from the water lines of the customer, utility workers flushed those lines. In case the water main had been contaminated, the utility workers had to flush the city’s distribution line, too. Until testing showed authorities that the city’s water was safe, they warned customers in the area not to drink it.

Stay in compliance with scheduled test. Be sure every connection within distribution system has some form of protection. Be sure protection meets degree of hazard requirements. Most importantly “Working Together” from water purveyors to inspectors, to contractors and you the consumer. It takes all of us to preserve and protect one of our most vital resources-WATER.

The referred to “Testing” is to ensure that each independent spring loaded check is holding at the required psi (pounds per square inch) and that if applicable the spring loaded relief valve also opens at required psi. This is to ensure the proper function ability of the assembly and more importantly to ensure your drinking water is safe.

For more information about backflow and cross connection control, visit www.tceq.texas.gov/goto/cc