Backflow Prevention: An Overview

Please fill out the form here to update your information. If you have questions about Backflow Prevention, please review the below information for more details and learn how it all works. You can also visit our blog post for further info.

We are pleased to partner with Backflow Solutions Inc. (BSI) to manage test records and assist you with annual backflow device testing. BSI provides customers reminders, guidance, and resources to help you stay on top of your backflow prevention device. If you have any questions related to backflow prevention, please reach out to BSI’s customer service center at 888-966-6050 or support@backflow.com

What is Backflow?

Backflow is when a drop in the incoming water pressure allows a reverse flow from a homeowner’s plumbing system back into the public water system. For example, if you have a garden hose submerged to fill a bucket, Jacuzzi, fish tank, etc., and the water system suddenly loses pressure, the flow of water can be reversed, sucking any contaminants in the water backwards into the system.

A Cross-Connection is any physical connection between a possible source of contamination and the public water system. For example, if a homeowner uses a cistern or an old well for outdoor watering, it cannot be connected to pipes that are connected to the public water system. Even with a bypass valve in place, it is prohibited.

Why is Preventing Backflow Important?

Cross connection control is extremely important in public water systems as it is a matter of public health and safety. Many contamination issues in public water systems, including bacteria from sewage, are not due to the water source but are due to cross-connections. Therefore, it is very important that all customers are aware of the dangers and take necessary precautions. We ask all customers to notify us if they currently have or require a backflow prevention device to safeguard against these potential hazards. For comprehensive information and support, including how to identify if you need a backflow prevention device or submit an existing device, please complete and submit the form included on this webpage
Backflow Prevention Diagram provided by CSWR. There are three columns of text and iconographical images. The first column shows a normal flow of water, with a public water supply running into a residential home. The additional text underneath states 'Pressure in the water system keeps the flow of water in one direction.' In the second column, it shows what is known as a Backflow Event Without Device; the image shows contaminated water flowing from the residential home into the public water supply, with the text underneath stating 'Loss of pressure in the water system creates a reversed flow of water, leading to the contamination of the public water supply.' In the third column, it shows an image with the residential home going through a backflow event, but the contamination is prevented from entering the public water supply by a device, and text that reads 'Backflow Event With Device: The reversed flow of water is stopped at the device, keeping the public water supply free of contamination."

Examples of Cross-Connection and Backflow Scenarios

  • Water softener, under-sink reverse osmosis unit, or water filter discharge tubing connected to a drain creates a direct connection to the sewage system.
  • A bottled water system such as a water cooler that is connected to the home’s plumbing system could contaminate the water system if the bottled water becomes contaminated.
  • A toilet in your home installed prior to 1964 that does not have an anti-siphon fill valve to prevent backflow from the tank into the water supply.
  • Soapy water or other cleaning compounds could back siphon into your water supply plumbing through a faucet or hose submerged in a bucket, basin, or mop sink.
  • An aquarium, dishwasher, or sink that fills from below the normal water level provides a conduit for contaminants to enter the water supply plumbing.
  • A hose submerged in a swimming pool creates a pathway for pool water to enter the water supply plumbing.
  • Fertilizers/pesticides or animal waste can be drawn into the water supply plumbing from a lawn irrigation system with submerged nozzles.

What Can You Do?

  • Be aware of and eliminate cross-connections.
  • Maintain air gaps. Do not submerge hoses or place them where they could become submerged (create a gap of air between supply and container, see attached photographs).
  • Use hose bib vacuum breakers on fixtures (hose connections in the basement, laundry room and outside) (see attached photograph of a hose bib vacuum breaker).
  • Make sure toilets have anti-siphon ballcock assemblies.
  • Install approved, testable backflow prevention devices on lawn irrigation systems. Contact your water system on acceptable backflow devices to be installed and testing requirements.
  • Do not create a connection between an auxiliary water system (well, cistern, body of water, puddles) and the water supply plumbing.

Backflow Prevention Residential Form

If you are a commercial customer, click here to download the Commercial Backflow Exemption Form.

* = required

    Public Water Supply Name

    Please select your utility provider:*

    Contact Information

    First Name*

    Last Name*

    Email*

    Address*

    City*

    State*

    ZIP*

    Phone

    Backflow Required Information

    Provide backflow device make and model:

    Provide backflow prevention device serial number:

    Date of last test result:

    Backflow Prevention Frequently Asked Questions

    What is Backflow? +
    What is backpressure backflow? +
    What is back siphonage backflow? +
    What is a cross connection? +
    What are some examples of cross connections? +
    How do I know if I need a backflow prevention device? +
    Is there a general compliance schedule and process? +
    Who can install a backflow prevention device? +
    Where should my backflow prevention device be located? +
    Who owns and is responsible for testing and maintenance of the backflow prevention device? +
    Why must a backflow prevention device be tested annually? +
    If you identify any cross-connections that cannot be eliminated you must install a backflow prevention device to ensure continued water service. Please submit your annual Backflow Field Test Report to env.comp@cswrgroup.com. Additional resources are available from the American Backflow Prevention Association at https://www.abpa.org/.