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What Causes Backflow in Plumbing?

Posted: July 16, 2019 to

There is no denying the fact that water is an essential part of everyday living. Clean and uncontaminated water is a fundamental human need, and we all, without any exception, deserve that.

With modern water supply systems in place, clean water has become more accessible. You twist the tap, and sparkling freshwater comes gushing down into your glass. However, if the tap stops supplying clean water, there is nothing we can do other than panic. Backflow is one of the biggest problems one might face in a modern water supply system.

Not sure what exactly is backflow and how does it affect the water that is supplied to our homes? Well, we’ll try to answer that.

Backflow happens when water flows in the opposite direction that it’s intended. Simply put, Backflow is a term in plumbing for an unwanted flow of water in the reverse direction.

Whenever the supply flow reverses back to the main water line, there is an increased chance of water contamination which may lead to serious health complications.

How Does Backflow Turn Into a Health Hazard? 

Backflow is the undesirable reversal of the flow of water or mixtures of water and other substances back into the public drinking water system. Often leading to a boil water notice. A common water problem after a hurricane in Southwest Florida.

The public water supply system supplies both potable and non-potable water within the city limits.

In a water supply system, all water lines; including potable and non-potable water lines, are cross-connected at some points. These cross-connections are at a higher risk of water contamination if backflow problems take place. During a backflow, water intended for irrigation or other usages can reverse its flow and get mixed with clean water, turning drinking water into potentially unhealthy and unsafe for consumption.

However, in residential plumbing, the fluctuation in the water pressure can cause dirty water from the pool, sinks, and washing machines to flow back into the main water line and contaminate the entire water supply source within the house.

Typical backflow situations are:

  • Backsiphonage: When the water pressure on the supply end reduces or stops, a negative pressure is formed, making the water flow forward to gush back to the water supply source. This kind of backflow can occur due to a water main break or excessive usage of water.
  • Backpressure: This type of backflow is created due to a sudden rise in the pressure of the water flowing downstream compared to supply pressure. When that happens, the water flowing downwards gets mixed with potable water lines.

Preventing Backflow From Polluting You Drinking Water

When it comes to safeguarding your clean water,  take a few minutes to check if there is a potential backflow situation in the water lines. A professional plumber can help you find out the possibilities of backflow and fix it before it further pollutes your main water lines. However, modern water fixtures like sinks, showers, and faucets are designed to prevent backflow from happening. There is no problem with being extra cautious in preventing a future backflow problem.

Here’s how to prevent backflow problems at your house. Many of these techniques should be done by a licensed plumber.

  • Air Gap: Creating an air gap is one of the most common techniques to prevent backflow. In the water supply outlet, vertical separation is formed which is two times the diameter of the supply pipe. The gap is placed at the end of the supply line, where it helps in maintaining positive water pressure in the pipes.
  • Backwater Prevention Device: The air gap is not always efficient in preventing backwater. In such cases, backwater prevention devices can come handy. The devices create physical barriers to counter backflow situations.

Here’s a list of some of the most commonly used backwater prevention devices.

  • Pressure Vacuum Breaker Assembly:  This type of device is useful in countering the back-siphonage issue. The water pressure in the lines is regulated with the help of a spring-loaded check valve and dual shutoff valve. Besides being cost-efficient, PVBs are simple in design and easy to install and maintain. However, there is a downside to this type of device. Pressure Vacuum Breakers may spill water every now and then. When planning to install this system, consider using a spill-resistant one.
  • Double Check Valves: if you are looking for an underground or indoor backflow prevention device, DCV will serve your purpose well. The installation consists of an inlet shutoff valve and two separately operating spring-loaded check valves.
  • Reduced Pressure Zone Assemblies:  Reduced Pressure Zone Assemblies are also called reduced pressure principle assemblies. Out of all the other backflow prevention devices, RPZA is the most efficient and reliable one. The installation consists of an inlet shutoff valve, two spring-loaded check valves separated by a pressure differential relief valve, test cocks, and an outlet shutoff valve.
  • Atmospheric Vacuum Breaker: This type of device is one the most inexpensive and the easiest backflow preventer devices for irrigation systems. The breaker is usually installed at the end of the pipe to check on the water pressure and prevent any backflow mishap.

If you have backflow issues at your house or just a quick question or need plumbing tips, feel free to give us a call or contact us through our website today.

About Aqua Care

We service more than 800 water systems throughout Lee and Collier County on a regular basis.

The various types of systems we install and service range from the standard aerator water system to the more modern twin tank water systems designed to remove offensive odors and soften the water.

We also maintain point of entry, or the whole house, reverse osmosis systems.

Contact us today: (239) 939-3656

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