How Much Does Backflow Testing Cost? (Guide 2023)

As you should conduct backflow testing once every year, it is important to know the backflow testing cost and how it varies. The valves will be inspected by licensed plumbers to check the functionality, and they will then report the status of the test. Before you find out about the cost, you should know what backflow is and how it may affect your water system. 

backflow testing cost

What is Backflow?

As the name implies, backflow occurs when water flows in the opposite direction of the intended projection. So when water backflows, you will have contaminated water depending on the situation. It even pollutes the water resources with noticeable changes in the color, smell, and taste of water. Therefore, it is important to prevent water backflow. Thus, you should use backflow-preventing devices. Before finding out the mechanism of backflow preventers, let’s identify how backflow occurs.

Back Pressure

If the plumbing’s pressure exceeds the pressure in the water distribution system, it is known as back pressure. So it is clear that back pressure occurs when the supply has a lower pressure than the pressure in the system. Thermal expansion caused by unvented heating systems is also a reason that causes this. Water systems with a higher elevation on the receiving side can have backflow issues quite often. This will be a major issue if you do not install your systems, such as outdoor sump pumps, correctly.

Back Siphonage

This is another reason for backflow in water systems. It happens when the pressure drops drastically due to sudden overuse or a higher withdrawal rate. This, too, happens with the rapid reduction of supply pressure when the supply is interrupted or drained down. The best way to eliminate these situations is by a backflow preventer.

What is Backflow Preventer?

A backflow preventer ensures that the water flows in one way without reversing its direction of flow. This is similar to a one-way gate where the flow is unidirectional. If the pressure changes in the system due to some circumstance, the backflow will function to prevent the backflow. Hence, it protects the water supply from cross-contamination and any similar risks. It is important to install a backflow preventer, especially for well-water systems where the risk of contamination is higher.

What is Backflow Testing and Why Do You Need It?

Backflow testing is an inspection done on your plumbing system to make sure that it prevents backflow. This testing is important if the pipes experience a sudden drop in pressure due to bursting or freezing during winter. A backflow may also occur if the water supply demand increases abnormally due to some reason. Thus, contaminated water from the ground or storage may seep into the system. 

Backflow testing is very important since it ensures that your water system is safe from any possible backflow. Some municipalities require annual testing, but not every region has that requirement. But it is important to add this backflow testing as a part of your house maintenance schedule to make sure that your family uses clean and safe water.

If you have never conducted a backflow test, you are not aware of any damaged parts in the backflow assembly. It is extremely dangerous as you might be consuming contaminated water for a long time. So, conduct a professional backflow test at least once a year to keep your family safe.

The Average Backflow Testing Cost

There is no specific set price for backflow tests in the US. The backflow preventer inspection cost depends on the experience and professional qualifications of the plumber. Certified plumbers will charge more than uncertified ones. The average backflow testing cost is somewhere between $150 and $250. But this can also vary from $20 to $500 depending on various factors. You can clarify the price ranges by referring to the table given below.

Low Cost Range$75 – $150
Average Cost Range$150 – $250
High Cost Range$250 – $500
Commercial Cost$350 or more

What Are the Factors That Impact the Cost?

So what exactly are the factors that influence the cost of backflow testing? It depends on various aspects, including the plumber and even the certification and city fees. The following are the main factors that have a direct impact on the cost of backflow testing.

Repair and Replacement

If your backflow preventer fails the test, then it needs to be repaired or replaced immediately. It will add to your expenses and increase the overall cost. But if the professional whom you hired cannot handle the repair, then you will have to pay another plumber as well. So hiring a testing person who can conduct the test correctly and handle any repairs will save you some money.

Retesting Failed or Repaired Devices

Once the backflow preventing system is repaired or the device is replaced after a failure, you should run the test again to confirm its function. It will surely add extra testing costs to the initial testing that failed.

Additional Cleaning

Flood water or mud can clog the backflow preventer which will make the plumber dig to get to the valve. Since this is additional work, he will charge you more than the cost of testing.

City Fees and Certification

Some cities need you to submit both positive and negative test results for review. This will cost you an additional charge. Most municipalities need you to have a backwater valve attached to a portable water supply. Also, it should be tested by a certified backflow tester once every year.

The Standard Procedure of a Backflow Test

The testing method will vary depending on the tester. Factors such as whether it is a sprinkler system, water supply, potable water line, or irrigation system will also determine the process. The main steps of the backflow test are as follows.

  • General inspection of the valves and the water line to check that everything is installed correctly according to the code. 
  • Confirm that the serial number is correct and that it is the right assembly.
  • Inspect to make sure that there are 4 test ports and 2 shut-off handles.
  • Attach the equipment and carry out the testing procedure for the assembly.
  • Finding any leaks and signs of corrosion in the installation. 
  • Filing the relevant testing reports with the city officials and the water supplier.

How Long Does Backflow Testing Take?

The backflow testing usually takes about 20 – 30 minutes for a certified plumber. But if the installation needs any repairs or replacement of parts, then it will consume more time. The plumber will let you know how long the repair will take once he inspects the system.

Frequently Asked Questions

How Much Does It Cost to Install a Check Valve?

The exact cost depends on certain factors including the size of the system. Generally, it will cost you something between $135 and $1,000 to install a check valve. The device costs between $35 and $600, while labor costs range from $100 to $400. So, you can expect the overall cost to be between $70 and $250 for a check valve installation.

Do I Really Need a Backflow Preventer?

Usually, homeowners with a well or irrigation system require a backflow preventer due to the higher risk of backflow contaminating the water source. Although a backflow preventer might not be needed everywhere, it is recommended to have one since it ensures that you consume safe water. Most new homes have backflow preventers in certain water lines. You can check this by getting a licensed plumber to inspect your water system.

Can I Use a Check Valve Instead of a Backflow Preventer?

Although check valves have various important applications, it is not a safe substitute for backflow preventers. It should not be used, especially for water systems involving drinking water. The backflow preventer is used for high-risk situations and the design protects the system completely from any possibility of contamination. The check valve is used for low-risk occasions where a possible backflow might not have critical effects.

Can I Use a Check Valve for a Sprinkler System?

Check valves are usually built into the body of the sprinkler to prevent water leaking from the lowest sprinkler in a zone. So, the check valves prevent unnecessary drainage, which wastes water. The sprinkler head check valve helps in using water sparingly as it reduces the amount of water needed to fill the pipes when the sprinklers start running every time.

Where Should a Backflow Preventer Be Installed?

The backflow prevention assembly should be installed inside an enclosure located above the ground. It is safe and more cost-effective to have the backflow preventer than having it underground. Backflow preventers should have a minimum distance of 12 inches above the ground. There should be enough clearance around it for testing and repair purposes. 


There are certain options such as DIY kits where you can test the backflow preventer. But it is recommended to hire a licensed backflow assembly testing professional to do the inspection. It is important, especially since the annual backflow testing is needed by certain municipalities. It will keep you at ease since you know that your water is safe without any contamination.