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What is Backflow Testing? A New York City Plumber Explains

February 22, 2021


During a backflow test, a certified backflow tester checks backflow prevention devices (also referred to as BPDs or RPZ) in a plumbing system to make sure they’re working properly and that the public water supply isn’t being contaminated.

The term “backflow” refers to when water in a plumbing system’s supply line flows in the opposite direction (out of the plumbing system instead of into the system). Backflow is problematic because it can cause the public’s water supply to become contaminated with human waste, harmful chemicals, etc.

In this article, we’ll explain:

  • How and why backflow occurs
  • What a backflow prevention device is
  • What’s involved in the backflow testing process
  • When (and why) backflow testing is required

Need a backflow prevention device installed or tested? Ranshaw is certified inBPD installation and testing. We have 50+ years of experience helping NYC businesses stay safe, code-compliant and avoid expensive DEP fines, and we can help you too.

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How does backflow occur in the first place?

Like we mentioned in the beginning, water that enters your home or business should only flow in one direction: into your home or business.

However, a change in pressure within the pipes can cause the water to flow backward and seep back into the public water supply. And when this happens, the public water supply can become contaminated.

What causes a change in pipe pressure?

Your pipes will experience a change in pressure if...

  • Your plumbing system has a leak
  • A city water supply line has a leak
  • A fire hydrant is being used near you

Because the pressure in your pipes can change due to the scenarios listed above, many homes and businesses in the NYC area are required by law to have a backflow prevention device.

What is a backflow prevention device (BPD)?

To protect NYC’s main water supply, most businesses are required to install backflow prevention devices on their plumbing systems.

A backflow prevention device (BPD) acts as a one-way gate: it allows water to enter your plumbing system, but it blocks water from ever moving in the opposite direction—back into the public water supply.

Backflow prevention devices must be tested annually to ensure they’re working properly and protecting the public water supply.

What’s involved in the backflow testing process?

During a backflow test, a certified backflow tester will determine if your BPD is up to code and test to see if your plumbing system is experiencing any backflow.

To do this, the tester will connect a special backflow testing kit to the BPD and monitor gauges to see if there is any change in pressure. That will help them determine if your system is experiencing backflow, and what could be causing the problem (for example, a water leak).

Because the pressure in your plumbing system will need to be monitored, they’ll need to shut off the water main for about 30 minutes. This means your property won’t have running water during that time.

Keep in mind, some buildings may have multiple backflow devices. If that’s the case, each device will require testing.

If a device fails, repairs will be required. Once the repairs are completed, a subsequent test will need to be performed.

After the test is completed, a Backflow Inspection report (NYC DEP Gen-215B Report) must be submitted to the NYC Department of Environmental Protection (DEP). Once the DEP reviews and approves the report, they will mail a stamped copy back for your records.

Is backflow testing required?

Because of the potential health hazards caused by backflow, NYC requires certain properties to have backflow testing every 12 months by a certified tester. You should receive a letter in the mail to notify you when your building’s BPD is due for its testing.

Unfortunately, skipping or missing your annual testing can result in a costly violation of up to $2,000 and possible disconnection of your water service.

Examples of properties that will need a BPD and annual testing include:

  • Properties with multiple water service lines
  • Properties with swimming pools
  • Properties with in-ground irrigation sprinklers
  • Large residential dwellings that use treated water boilers
  • Food preparation facilities
  • Laundromat and dry cleaners
  • Schools and colleges
  • Supermarkets
  • Car washes
  • And many more

For a complete list of properties required by law to have a BPD and regular testing, visit theNYC Department of Environmental Protection backflow FAQ page.

Need backflow testing from a certified NYC tester?

Whatever your backflow needs, Ranshaw can help.

For 50+ years, we’ve installed and tested backflow prevention devices for hundreds of NYC buildings. We make your backflow testing easy. After your first backflow inspection with us, we’ll send you convenient reminders every year when it’s time for your next annual test. Plus, we even file your paperwork with the DEP on your behalf.

All you have to do is call Ranshaw and we’ll handle it all!

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