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Backflow Prevention

Choose a Licensed Maryland Plumber for Backflow Prevention

Plumbers 911 Experts Help Keep your Drinking Water Clear & Pure

Backflow Prevention | Maryland Plumbers

Of all the various functions that our home plumbing systems perform, one of the simplest but most important is providing us with our daily drinking water. But because plumbing systems are so complex, it’s always possible for our drinking water (also referred to as our potable water supply) to be in jeopardy due to contamination by wastewater from other parts of the system. This unwanted cross-contamination is called “backflow,” and it’s possible that your home plumbing could be susceptible to backflow occurring.

This is particularly true if your home has a sprinkler system, irrigation system, or other complex plumbing systems that could potentially cause contaminated water to mix with your drinking water. Backflow could contain hazardous waste such as fertilizer or pesticides, dangerous chemicals, or human waste. Obviously, it isn’t something that you want to risk threatening the water you drink. Thankfully, it’s a fairly simple problem to both prevent and correct.

If you’re worried that backflow may be an issue in your home, continue reading to learn more about what causes backflow and how you can be sure it doesn’t occur within your plumbing system. Backflow might sound ominous, but it doesn’t have to be! Contact a licensed Maryland plumber today to have one of our expert technicians talk to you more about backflow prevention, and help you decide if it’s something that your system would benefit from installing.

What causes backflow?

In sum, backflow is caused by a pressure differential between the potable and nonpotable parts of a plumbing system. There are two main kinds of backflow: backpressure backflow and backsiphonage. Although each has a different cause, both are preventable.

  • Backpressure backflow
  • Backsiphonage

If you’re worried about issues with backflow in your plumbing system, having a professional plumber diagnose the potential hazards in your system can be the first step towards a permanent backflow prevention solution.

Backpressure backflow: This kind of backflow is caused by a difference in pressure between the nonpotable system and the water distribution system. This might happen, for example, when the pressure from a boiler system becomes greater than the water pressure of the water distribution system. In this instance, backflow would occur.

This change in pressure can happen when an unusual stress is put on the water supply, and the demand on the system is greater than the water available. Examples of this include when a fire hydrant must be used to fight a fire, or when a water main breaks.

Backsiphonage: This is essentially the opposite of backpressure backflow. It occurs when there is negative pressure in the water supply system, creating a vacuum that draws in contaminated backflow into the potable water supply. As before, this vacuum can be caused by an unusual strain on the water supply, such as when a fire hydrant is opened by firefighters. The sudden release of a large amount of water quickly lowers the water pressure, causing a vacuum.

In addition to these more unusual situations causing backflow, it can also occur due to regular use of household water, such as when running a garden hose. Improperly installed toilets can also be culprits in causing backflow.

How can backflow be prevented?


There are several devices that can be installed to prevent backflow. Which one is right for the job depends on the individual needs of each situation. If you think that your plumbing system requires backflow protection, contact Plumbers 911 Maryland to have a professional recommend the best solution for you.

Here are some of the most common backflow solutions:

Backflow Prevention | Maryland Plumbing ServiceAir Gap: This is the simplest solution for preventing backflow. In essence, an air gap is a small device that creates a barrier between a non-potable water source and potable water. In the chance there is excess non-potable wastewater, the air gap provides a space for this water to overflow into, as well as small holes to releave any built-up pressure. For example, an air gap might be used to protect the kitchen sink from excess wastewater created by the dishwasher.

Reduced Pressure Zone (RPZ) valve: This is a small mechanical device that consists of two valves that work together to prevent backflow. These valves work to relieve pressure in instances where otherwise backflow might occur.

Pressure Type Vacuum Breaker (PTV): As the name suggests, this device works to release pressure and prevent the development of a vacuum that could cause backsiphonage. However, it does not work to prevent backpressure backflow, so it is used in certain situations where only backsiphonage is a risk.

Atmospheric Type Vacuum Breaker: Like the PTV, this device is specifically used to break vacuums, and does not prevent backpressure backflow. These devices incorporate an atmospheric vent, which opens to relieve pressure when a potential vacuum is detected.

Barometric Loop: Another method of preventing backsiphonage, this method involves a tall pipe arranged in a loop that allows water to flow over the loop, relieving pressure.

There are many methods of backflow prevention because there are many individual situations and needs, depending on the complexity of your system and the demands placed on it. A professional eye will quickly be able to determine which one of these solutions is the best for you.

Why hire Plumbers 911 Maryland?

If you’re concerned about preventing backflow in your plumbing system, then one call to Plumbers 911 Maryland should be your first step. You’ll reach a network of the top industry professionals in our region, and can rest assured that you’ll receive the best quality service at a price that’s competitive.

Every one of our expert plumbers is highly trained in the newest methods and techniques, and will quickly be able to determine the best backflow prevention solution for your needs.