Backflow Preventers

Backflow Preventer

Backflow preventers are devices used to prevent the reverse flow of water in potable water systems.  They are used in both residential and commercial applications, and can vary from a simple, inline “check valve” to much more complex contraptions.  In this article we will take a look at some of their uses, and why they are needed.

Residential Uses

When most people familiar with the term backflow preventer here it, they automatically think of the big, commercial Reduced Pressure Principal Assemblies.  You may be surprised to know that there are actually a lot of backflow prevention devices in your very own home.  Knowing what they are can be helpful.

If you have a pressure regulator in your home, it is also a backflow preventer.  The purpose, in this case is to not only regulate the water pressure going into your home, but to protect the city water supply from “contamination” from the water in your home.

Another common use is irrigation control valves (sprinkler vales).  ICVs are built with a check valve, and a built in “air gap” to keep irrigation water from flowing back into your home.  In fact, as long as we are on the subject, current plumbing code requires that you have backflow preventers on your hose bibs as well.  They function much like ICVs in that they bleed excess water through bleeder holes, rather than let it flow back into the home.

While those are three, fairly obvious examples, there is another one that is not quite as obvious, but even more common… your toilet fill valve!  Yup, every toilet fill valve has a check valve and a bleeder to prevent the water from your toilet tank from seeping back into your home’s water supply.  That is just one of the many fixtures in your home that employ some form of backflow prevention.

Commercial Uses

Most commercial building these days have at least one backflow preventer.  Many of them have 2 or more.  Have you ever seen those big devices (like the picture at the top of this article) in front of buildings?  You may even have seen them covered by a big cage.  Those are commercial backflow preventers.

  • A few places where you are most likely to find them are:
  • Between the meter and the building, for the main water supply to the building
  • Between the meter and the irrigation control to service the sprinkler system
  • At the beginning of a fire sprinkler system
  • Separating industrial machinery that uses the building water supply.

Important things to consider

While a qualified, experienced plumber can diagnose problems, repair and replace residential backflow preventers, they cannot repair or maintain commercial ones.  A good plumber can install them, and often tell you if one has failed, it requires certification to actually perform maintenance on them, or repair them.

While residential units require very little maintenance (it is usually less expensive to just replace faulty units), large, commercial units (such as RRPs) require regular maintenance.

Although backflow preventers are used in fire sprinkler systems, neither a plumber nor a certified backflow specialist can work on those.  Any work on fire sprinkler systems have to be done by a licensed fire system specialist.

If you have more questions about backflow prevention, give Gogo Rooter Plumbing a call.  We are there for you to answer your questions, and help solve any problems you may have with backflow preventers.