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Landry Mechanical Inc Plumbing HVAC & Electric Blog

Understanding What Plumbing Backflow Is and Why It Happens

Backflow is one of the most dangerous plumbing issues you can face. In addition to damaging your pipes, backflow can also contaminate drinking water and make you sick. To keep backflow from occurring, it is necessary to understand why it happens and how you can stop it.

What Is Backflow?

Backflow is a type of plumbing problem that occurs when your wastewater does not flow in the right direction. Instead of flowing down into your sewer system, the wastewater instead travels into your fresh water supply. There is a variety of different situations that can count as backflow. In some cases, backflow can cause dramatic gushes of discolored water from your faucets. In other situations, backflow can be so subtle that your water supply’s color, smell, or taste might not change noticeably.

There are several different ways that backflow can happen. It is usually divided into back-siphonage backflow and back-pressure backflow. Back siphonage occurs when a vacuum inside of your pipes physically sucks wastewater backward. Meanwhile, back pressure happens when excessive wastewater pressure causes wastewater to flow in the opposite direction.

Both types of backflow have the same basic result. You end up with wastewater from your toilets and drains coming out of your faucets. The contaminated water supply can cause a huge, disgusting mess throughout your home. Even smaller levels of backflow are still problematic. You might not notice a difference, but you can still get sick from the toxic chemicals and dangerous microbes in wastewater. Backflow is also dangerous for your pipes. When your plumbing system has backflow, your pipes are more likely to corrode, warp, or develop leaks.

How to Tell if You Have Backflow

Since backflow can happen so gradually, you might not realize you’re dealing with this plumbing issue. Backflow can usually only be confirmed by testing your water quality.

Here are a few signs that it might be time to test your home for backflow.

  • Strange odors around your faucet
  • Slow moving drains
  • Water that is brown, yellow, pink, or otherwise discolored
  • Strong sulfur smells from your water
  • Odd tastes in your water
  • Small particles floating around in your water

Causes of Back-Pressure Backflow

The water pipes throughout your home are all part of a carefully balanced system. A combination of pipe size and pipe placement is supposed to ensure that upstream water supply pressure is always higher than downstream water removal pressure. Water flows in the direction of least resistance, so this allows the clean water to “push” wastewater away from any water supply pipes. However, some plumbing mixups can cause pressure in water removal pipes to become higher than the water supply pressure. When this happens, the wastewater flows back upstream, causing a back pressure backflow to develop.

Back-pressure backflow often happens when your plumbing system was installed incorrectly. There are a lot of little mistakes that can add up to cause water pressure differentials. This is especially true if your plumbing system includes pressure-producing fixtures like elevated water tanks, boilers, or water heating systems. These can dump a lot of water into your drains at once, resulting in backflow. Even small things like the heat expansion from a boiler can increase pressure in the wrong part of your pipes. These disruptions may change water pressure levels enough to cause back pressure backflow to happen.

Back pressure backflow is also sometimes caused by a plumbing problem. If you have a leaky pipe, water supply pressure can drop just enough to let other plumbing issues make your wastewater pressure higher than your water supply pressure. Problems with your wastewater removal lines may also increase downstream pressure. If you have a clog in a drain line, water can back up behind the clog, increasing pressure enough to result in backflow.

Causes of Back-Siphonage Backflow

Back-siphonage backflow is also linked to uneven water pressure levels, but it’s more drastic. Instead of water just accidentally flowing in the wrong direction, back-siphonage happens when a vacuum occurs. The negative pressure can pull wastewater up into your supply lines very suddenly and sharply. Back siphonage is less common than back pressure, but it can result in more clearly contaminated water.

Back siphonage tends to happen when a lot of water is suddenly removed from your water supply system. It is most commonly associated with firefighting efforts. When firefighters are using a hydrant, the extreme drop in water pressure can end up forcing wastewater up into your water supply. Back siphonage can also occur when a water main break lets all your potable water spray out of your system. This tends to create a vacuum in water supply pipes that lets back-siphonage develop.

How to Prevent Backflow From Affecting Your Home

As you can see, there are multiple ways for backflow to occur inside your home. Some of these causes are preventable. Keeping your plumbing system up to code is one of the best things you can do. Local building laws regulate pipe sizes, placements, and angles to help minimize the risk of backflow.

You also need to remember that your entire plumbing system is designed to work together. Doing something like adding a new boiler can disrupt water pressure levels everywhere. To prevent these sorts of plumbing mistakes, you should consult with professionals any time you want to change part of your plumbing system or install a new fixture. They can help you figure out if your wastewater and water supply lines are up to the task.

Even if your plumbing system was perfectly designed, outside forces can still cause backflow to happen. To protect your home, it is a good idea to try some backflow prevention measures. There are a variety of plumbing add-ons that force water to flow in a single direction. These are very useful for halting backflow in case of a water line break or another issue. To protect a single faucet, you can install a hose bib backflow preventer. This compact, affordable device uses a spring-controlled seal to keep water from flowing backward. Another similar option is a pressure-type vacuum breaker. This device continuously monitors water pressure for a specific part of your system and closes a valve if it detects an imminent backflow.

Other backflow prevention measures can be installed within your plumbing system to provide more widespread protection. Barometric loops and air gaps are two styles of pipe placement that help regulate water flow and prevent siphoning. You can also use options like a reduced pressure principle backflow preventer. These more complex systems use multiple valves to control water pressure, and they can protect your whole home from any backflows.

If you are concerned about backflow, it is essential to get professional input. At Landry Mechanical Inc Plumbing HVAC & Electric, our highly trained technicians can help you get your plumbing up to code and stop backflow in its tracks. We serve the central Massachusetts area around Brookfield and Grafton, and we provide a wide variety of HVAC, plumbing, and electrical installs and repairs. To learn more about the services we offer, give us a call today.

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