When talking to an irrigation specialist, you will hear a lot of jargon. One of those is backflow, which goes along with backflow preventer valves. Your installer will no doubt tell you how important it is to prevent backflow.
Backflow is when water (or another fluid) flows through a piping system in the wrong direction. It is most often caused by a sudden drop in water pressure, which can happen any time you are attached to a municipal system – like if the fire service opens a hydrant a few streets over.
Any kind of backflow is bad. If, for example, you have a lawn irrigation system in your yard, the water used for irrigation will sit in underground pipes for days before the system turns on. Contaminants such as fertilizer, lawn care chemicals and even pet waste can be drawn back into the system if backflow occurs. Backflow can transmit this contaminated water back into the municipal piping system or even your home’s piping system. In industrial systems, backflow can also cause cross contamination with the municipal system or even contamination among other fluids used within the industrial process.
Other than avoiding sudden water pressure drops, which are not always avoidable, backflow is prevented by a backflow preventer or valve. There are a variety of types, depending on the application and risk of backflow contamination. The type of backflow prevention device required is usually dictated by local and state codes. Your local water purveyor usually has a list of approved backflow prevention devices available on their website. A backflow preventer contains check valves that only allow flow in one direction. If a sudden drop in pressure occurs upstream of the backflow preventer, the check valves will close and block the flow of water back “upstream” into the system.
Preventing backflow is a key aspect of proper design of an irrigation or piping system. Contact a professional such as W.P. Law, Inc. to help you prevent potentially contaminated water ending up in your kitchen faucet, or worse.