Backflow FAQ


What is backflow?

When the water in pipes goes in the opposite direction from its intended direction of flow, a problematic condition called “backflow” occurs. Springfield Utility Board (SUB) controls water quality up to the point of the water meter. After this point, water quality can be degraded or contaminated within a private property plumbing system. When backflow occurs, water from inside a private plumbing system can be pushed back (backpressure) or pulled back (back siphonage) into the community’s drinking water supply. On a smaller scale, backflow can be isolated within a single property when water from a source, like a sprinkler system, pushes or pulls the water back into the property’s drinking water supply.

There are two situations that can cause the water to go backward (backflow):

  • Backpressure – the water pressure in your pipes is greater than the pressure of water entering your pipes.
  • Backsiphonage – a negative pressure (vacuum or partial vacuum) in one of the pipes. This situation is similar in effect to the sipping of water through a straw.
    Backflow prevention assemblies are used to help prevent backpressure and/or back-siphonage.
What is a cross-connection?

A cross-connection occurs when a pipe designed to carry safe drinking water is connected at some point to a pipe containing unsafe water or other liquid material. You may not think of your home as having such hazards, but if you have a hose that is submerged in a pool, carwash bucket, bathtub, or laundry sink, or if you have a pesticide sprayer connected to a garden hose, you’ve created a cross-connection. If a water main breaks, the potential exists for unsafe substances to be siphoned back into the water supply. This means that contaminated water in a pool, carwash bucket, laundry sink, or pesticide sprayer could be drawn into the water system. Once there, the contamination could affect many.

What is a backflow assembly?

A backflow assembly (also known as a backflow preventer) is mechanical plumbing equipment that is installed on your domestic plumbing service. Once installed and tested, rubber checks and springs inside of the backflow assembly will prevent any water from flowing in the reverse direction. Backflow assemblies must be tested annually.

All backflow assemblies must be both State approved, which are assemblies accepted and listed as approved by the University of Southern California Foundation for Cross Connection Research.

Causes of Backflow

SUB works hard to protect your drinking water from contamination. This effort begins at the well or watershed where your water is collected and continues through the entire treatment and distribution process. But did you know that water quality problems can occur after water reaches your home or business? Read on for some important information about the hazards of backflow, and the role water users play in keeping the pure water in your pipes free from contamination.

What are some backflow hazards at home?

How many times have you put a garden hose in a bucket of soapy water to wash the car? Or sprayed insecticide with a garden hose sprayer? Or attached a hand spray attachment to the kitchen faucet to wash your hair or the dog? These seemingly harmless actions create cross-connections that could endanger the health and safety of you, your family, and your neighbors.

The danger comes when the hose comes in contact with a harmful substance. If the pressure in the water main drops while the hose is submerged in contaminated water, then the water (and whatever is in it) could be sucked back into your pipes and the drinking water supply. Water pressure drops are not uncommon. They can occur when hydrants are opened to fight fires or during repairs to a broken water main. Fortunately, keeping your water safe from these contaminants is easy.

Are private wells a hazard?

Backflow can also occur in the absence of a water main pressure drop. For example, some customers have backup water systems connected to their homes’ plumbing. If these systems, supplied by private wells or springs, experience a pressure increase greater than that in the public water supply system, backflow will occur. Because these private supplies are not tested and regulated by governmental agencies, they may pose a hazard to the potable water system and must be equipped with proper backflow prevention devices.

What is a back siphonage situation?

Back siphonage is backflow caused by a negative pressure (vacuum or partial vacuum) in the supply piping. Back siphonage occurs when system pressure is reduced below atmospheric pressure and potentially contaminated substances can enter into the public water supply.

What is a backpressure situation?

Backpressure is backflow caused by pressure in the customer’s plumbing being greater than the pressure in the water supply piping, creating a situation where potentially contaminated substances can enter into the public water supply. The higher pressure in the customer’s plumbing may be from a booster pump, heating boiler, etc.

SUB’s Cross Connection Control Program

Why does the SUB Water Division have a Cross Connection Control Program?

The purpose of this program is to protect the health and welfare of the citizens of Springfield by ensuring that SUB’s drinking water supply is protected from harmful substances. As your public water supplier, we are required by the Oregon Health Authority under Oregon Administrative Rule (OAR) 333-061-0070 to maintain and enforce a cross-connection control program.

What are the Cross Connection Control Program requirements?

Both the SUB Board Policy and the Oregon Health Authority (OAR 333-061-0070) require that backflow assemblies be installed and tested annually by a state-certified backflow tester. SUB Water Division sends letters notifying customers of their duty to test their assemblies. If no action is taken, then SUB may shut off the water service until a backflow test can be scheduled, passed and verified by the SUB Water Division.

What types of water service lines require backflow assemblies? Who must comply?

Residential homes that have irrigation sprinkler systems, booster pumps, boilers, geothermal heating systems, or medical equipment connected to the SUB’s water system are required to have backflow assemblies on those systems.

In addition, SUB Water Division Cross-Connection Control Program requires commercial, industrial, public, and multifamily (more than 4 units) users to comply. Because these properties have larger service lines (and therefore pose a greater public safety hazard) and have tenants turn around, they are required to have backflow assemblies installed. In general, all new domestic, fire, and dedicated irrigation lines must have backflow assemblies installed to comply with the SUB Water Division Cross-Connection Control Program Full Manual (PDF).

What is the Utility doing to prevent cross-connections?

Because the protection of the water supply is critical to the health of our families, Board Policies give SUB the authority to inspect all residences and require the removal of cross-connections found. Non-compliance can result in the disconnection of water service to the user. This includes the largest industrial plant to the smallest individual home.

I received a letter saying I need to install a backflow assembly. How do I do that?

We recommend contacting a licensed plumber. You can install it yourself, but it must be installed according to our installation requirements, and we will inspect it after installation. If you hire someone to install it, provide them with a copy of the letter and installation guidelines enclosed in the letter. Once it’s installed, you or the installer should contact us to request an inspection. If it passes inspection, the final step is to have it tested by a tester from our Certified Backflow Tester List (PDF).


Why is a Reduced Pressure Backflow Assembly (RPBA) required on my irrigation system?

Irrigation systems include but are not limited to agricultural, residential, and commercial applications. SUB Water Division Cross-Connection Control Program Manual and the International Association of Plumbing and Mechanical Operators (IAPMO) classifies lawn sprinkler systems and irrigation systems as a high hazard for several reasons: sprinklers, bubbler outlets, emitters, and other equipment are exposed to substances such as fertilizers, fecal material from pets or other animals, pesticides, or other chemical and biological contaminants. Sprinklers may remain submerged underwater after use or storms. Should the water system pressure suddenly decrease, such as in the case of a water main break, or during a major fire involving multiple fire hydrants, these harmful substances can be back-siphoned into the water distribution system? They may be subject to various on-site conditions such as additional water supplies, chemical injection, booster pumps, and elevation changes. All of these conditions must be considered when determining backflow protection.

Is a Reduced Pressure Backflow Assembly (RPBA) the only assembly I can install on my irrigation system?

Yes, RPBA provides the best backflow protection against the high hazards of an irrigation system. The RPBA provides a warning sign when the assembly is failing and does not allow backflow to occur. A Double Check Valve Assembly (DCVA) is not allowed for new installation because it has no exterior indication of failure, which can be as high as 15%. This means a DCVA could have passed a test but started to fail soon after, a problem that would not be caught until the next annual test, leaving customers unknowingly without protection.

Pressure Vacuum Breaker (PVB) is testable, but proper operation requires the assembly and sprinkler heads to be installed at a certain height and the assembly must also pass testing. Even if the test for the PVB was good, the assembly’s operation may be compromised because of improper installation. A correctly installed RPBA is required instead of the PVB since the installation of the sprinkler heads downstream of the RPBA does not affect the assembly’s operation.

Atmospheric Vacuum Breakers (AVB) are non-testable devices that also require certain installation requirements for the device and sprinkler system. There is no test to determine if this device is working properly and the operation of the device may be compromised by modifications to the sprinkler system. A properly installed RPBA is required instead of the AVB since modifications of the sprinkler system downstream of the RPBA do not affect the assembly’s operation and the RPBA can be tested to verify proper operation.

Why is my backflow assembly installed above ground?

Existing Double Check Valve Assemblies (DCVAs) are installed above ground because in an underground installation the assembly is likely to become submerged in water during the winter months. If the assembly does get submerged underwater the manufacturer’s warranty is void. Also, above-ground installation of DCVAs is recommended by the Foundation for Cross-Connection Control and the Hydraulic Research University of Southern California, because a cross-connection between the test cocks and the water submerging the assembly is created.

Reduced Pressure Backflow Assemblies (RPBAs) are installed 12 inches above ground because this assembly dumps water when the assembly fails. Adequate drainage is needed to ensure discharging water does not back up and flood the assembly.

Are any other backflow assemblies required for residential homes?

All outdoor faucets and hose bibs that have threaded connections where a garden hose can be attached should have backflow prevention protection. This may be in the form of a frost-proof automatic draining outdoor faucet with a built-in backflow preventer or by the use of a screw-on hose bibb vacuum breaker (HBVB) that can be purchased at local hardware or home supply stores.

Note: Customers should take necessary actions to ensure that their backflow prevention assembly or plumbing does not get damaged during freezing temperatures.

How much does it cost to have a backflow assembly installed?

Since there are so many variables, such as pipe size, pipe type, location of installation, backflow assembly size and type, availability of a drain, and the plumber’s individual pricing, the SUB Water Division cannot provide an estimate of the installation cost. However, it is advised that you get at least three quotes so that you can compare installation costs.

How do I know if I have a backflow assembly?

Generally, the backflow prevention assembly is located as close as possible to the water service connection but must remain on private property. It is usually installed outdoors and in a “loop” of the irrigation system that extends above the ground and sometimes near the sprinkler system timer.

Is there a minimum height that the backflow assembly must be installed?

Yes, backflow prevention assemblies should be installed in accordance with the manufacturer’s installation instructions and the Water Division installation requirements. Regulations regarding flow orientation and proper access to the backflow assembly should also be followed.

A plumbing permit is required for the installation of a new backflow assembly or relocation of an existing assembly. Please contact the City of Springfield to obtain the permit.

What is the difference between a backflow device and a backflow assembly, and why are assemblies required?

Backflow devices are installed at a building’s taps and are not testable. Backflow assemblies are installed at a building’s water service connection and are testable and repairable, which is why they are required. Examples of backflow assemblies include a Reduced Pressure Backflow Assembly and a Dual Check Valve Assembly. Examples of a backflow device are a hose-bibb vacuum breaker, atmospheric vacuum breaker, or dual check with atmospheric vent.

What can I do to protect my home plumbing system from backflow?

Install a hose-bib vacuum breaker on each of your outside water spigots. These devices will prevent water from being back-siphoned from a hose or irrigation system into your home’s plumbing. Hose-bib vacuum breakers are inexpensive and available at hardware stores.

What can prevent cross-connections from occurring?

Backflow assemblies can reduce the risk and protect our community from widespread illness and disease. They are assemblies that prevent water from moving backward into the water system through combinations of check values or hydraulic breaks. Backflow assemblies come in many sizes, specifications, and degrees of complexity, depending on the problem being addressed.

I don’t use my irrigation system. Do I still have to test and maintain my backflow assembly?

As long as the irrigation system is connected to your plumbing system, the potential for backflow exists, and you must comply with all backflow requirements, including having it tested annually. To eliminate these backflow requirements, the irrigation system must be physically disconnected from your plumbing system.
If your irrigation system is served by the same water service that serves your home or business, you can have the irrigation system cut and capped. Once this is complete, contact us to schedule an inspection.
If your irrigation system is served by a separate irrigation meter, contact us to close the account and we will lock or remove the meter.


Who is responsible for paying for the assembly and testing?

It is the customer’s responsibility to ensure that any contaminants or pollutants do not enter the water distribution system from their location. All costs related to the installation, maintenance and testing of backflow prevention assemblies are the customer’s responsibility.

Will my water service be interrupted during the test?

Yes, the water supply to the backflow preventer must be turned off during the testing procedure. The type and location of the assembly will determine how long the test will take. Typically 10 to 30 minutes, are needed to complete testing. Additional time may be needed to make repairs.

What is the cost of the test?

Individual backflow assembly testers and testing companies set their own rates and their charges vary widely. We recommend that you obtain more than one quote. Over the past several years the average cost for testing a double check on an irrigation system has been $35 to $50.

Inspection and Maintenance

What will the inspectors be looking for?

Backflow from customer piping is the leading cause of contamination in a public water system. The State of Oregon rules requires the Water Division to protect against backflow by conducting site inspections. Inspectors will look for facilities that pose a severe or high health cross-connection hazard. Inspectors will also be looking for proper backflow protection on lawn irrigation systems.

How will I know what is found during the inspection?

The cross-connection inspector will be completing a “Residential Cross-Connection Inspection Form”. A copy of this form will be given to the property owner when the inspection is completed. On this form will be the results found during the inspection. It will show you what was found to be in compliance as well as what change(s) need to be made, if any, to protect your plumbing from possible cross-connections.

What do I need to do after the corrections are made?

Once the required plumbing changes have been made, just call the Water Division at (541) 726-2396 to schedule an appointment for a re-inspection. At the time of the re-inspection, the Cross-Connection Specialist will check that the necessary changes were made and note whether these cross-connections have been corrected.