What Is a Vacuum Breaker?

Nobody wants dirty water to come back into their home. When a major plumbing issue happens, having a working vacuum breaker can prevent you from dealing with a nightmarish cleanup situation. Our guide explains what a vacuum breaker is, the different types available, and signs of a failing breaker. 

What Is a Vacuum Breaker?

A vacuum breaker is a type of backflow preventer that uses air pressure to prevent water from flowing backwards. Water pressure may drop when there is a major leak or water break in the main line. As a result, a vacuum is formed, and the flow of water can be reversed. This is known as the “back-siphonage” process. A vacuum breaker allows air into the system to disrupt the siphon effect.

Types of Vacuum Breakers

There are three common types of vacuum breakers:

• Atmospheric vacuum breakers (AVBs): Consist of a check valve and an air vent. Often installed on outdoor faucets.

• Pressure vacuum breakers (PVBs): Rely on a spring-loaded check valve to operate under high pressure. Often installed in sprinkler systems.

• Hose bibb vacuum breakers (HBVBs): A removable anti-siphon valve that can be screwed directly onto outdoor faucets.

Signs Your Vacuum Breaker Is Failing

It will be too late when contaminated sewage water floods your property. Fortunately, there are clear signs your vacuum breaker may be failing:

• Water leaks: If you notice a frequent, ongoing leak at the base or around the valve, don’t ignore it.

• Water pressure change: A sudden drop in water pressure in your faucet or sprinkler system could indicate a problem.

• Unpleasant odor or taste: If you notice an unpleasant odor or taste in your water, a backflow might already be happening. Check your vacuum valve immediately.

• Dry or brittle seals: Damaged seals should be replaced to keep your vacuum breaker operable.

• Hissing or popping sounds: A leaking vacuum seal could lead to hissing or popping sounds in your pipes.

How to Repair or Replace Vacuum Breakers

Hire a local plumber if you need to inspect, service, repair, or replace AVBs and PVBs. For HBVBs, you can detach and replace them with new ones yourself fairly easily. Sometimes, you may only need to replace the aging seal instead of getting a whole new vacuum breaker.

The interior parts of a vacuum breaker typically last between 5 and 10 years. To catch failing parts early on, you should have your vacuum breakers inspected at least every three years. For vacuum breakers on your sprinklers, hire a sprinkler technician for the job.