How Much Does Backflow Testing Cost? The Ultimate Guide

Whether or not you’re aware, backflow can be a serious issue that jeopardizes your health and safety. A licensed plumbing company is advised. What is it? We’ve covered everything you need to know about backflow and the backflow testing cost.

Backflow prevention is a critical but frequently overlooked aspect of plumbing. Water can flow in either direction without a backflow preventer, posing a severe risk of pollution; on that account, let’s start with the basics.

What Is Backflow?

Backflow is a plumbing term when water flows in the opposite direction of the projected system. Homeowners may be exposed to contaminated potable water when backflow occurs, putting themselves and their families at risk. Building codes require several measures and backflow prevention devices to prevent backflow.

Backflow occurs when new, clean water mixes with dirty, used water. This pollutes your potable drinking water source. Backflow symptoms include noticeable changes in your water’s taste, smell, and color. When you look closely at backflow, you may notice elements that are supposed to be distributed away from your home, such as:

  • Fertilizers
  • Human waste
  • Pesticides
  • Pool/spa chlorine

Types Of Backflow Testing

Backflow occurs when water reverses its flow direction and begins to flow in the opposite direction. Serious contamination can occur, resulting in illnesses and even fatalities. As a result, it is critical to test for backflow and address any issues as soon as possible.

Backflow can occur due to two main causes: back siphonage and back pressure.


Back Pressure

Backpressure is caused by increased water pressure rather than decreased water pressure — imagine blowing through a straw and pushing water back into the glass instead. It occurs when the downstream pressure in a water supply exceeds the pressure at the source. 

Assume that clean water was flowing into fertilized fields via an irrigation system. If the irrigation equipment became clogged, the increased pressure could force fertilizer-contaminated water back into the clean water supply. 

Backpressure and backflow can also be caused by pump failure, increased downstream boiler pressure, and poorly pressurized elevated storage tanks.


Back siphonage 

Back siphonage occurs when water flows in the opposite direction due to a drop in water pressure. A water main break most commonly causes it. A car could collide with a fire hydrant, causing it to spout water into the air and create the same vacuum effect. 

Assume a laundromat was nearby connected to the same water system as the fire hydrant. Because of the hydrant break, the drop in water pressure could suck dirty wash water back into the clean water supply, much like a person sucking water through a straw.

The most common cause of backflow at home is a garden hose that loses pressure and sucks dirty water backward from the garden into the potable water supply.

Preventive Measures Of Backflow Testing

Water distribution systems are built to keep a high enough pressure to allow water to flow from faucets, showers, and other water fixtures. A properly functioning backflow preventer safeguards clean water supplies against polluted or contaminated water caused by backflow.

When water pressure is lost due to burst or frozen pipes, polluted water from other sources travels backward, eventually entering the potable water distribution system. Air gap and backflow prevention devices come into play at this point.

Few Devices That Are Used To Prevent Backflow

Backflow prevention devices are installed in every house plumbing system to avoid mixing contaminated and drinkable water. When the water supply is contaminated, serious health issues may result. Typical plumbing systems maintain water pressure to ensure that water can flow from showers, faucets, and other fixtures. 

The decreased water pressure, however, can let polluted water flow back into the supply system if the pressure breaks, for instance, if nearby water main explodes or the family uses a lot of water. Backflow prevention devices are used to prevent such hazards. This kind of device is typically installed in a home’s exterior water tap to avoid contamination.

Since the type of backflow preventer relies on the level of danger, pipe size, location, and testing, your plumber will be able to advise you on the best backflow prevention devices to install in your home. Here are a few devices that plumbers frequently use:

  • Air gap
  • Chemigation valve
  • Double check valve
  • Pressure vacuum breaker

Air gap

The most economical and trustworthy backflow prevention method is usually an air gap.

An air gap is employed to stop backflow from rainwater and other water supply tanks into the mains-supplied water system. Additionally, they prevent contamination backflow from fixtures or appliances connected to the water supply.

Provide a dedicated water supply with an authorized air gap for swimming and spa pools. The air gap must be at least 25 mm wide or twice as wide as the supply line.


Chemigation valve

A backflow preventer, often referred to as a check valve or a chemigation valve, guards water sources from agricultural chemicals used during chemigation, which is the delivery of fertilizers and pesticides through irrigation water.

 A spring-loaded check valve, a low-pressure drain, an air and vacuum relief valve, and an injection port for introducing chemicals downstream of the check valve are common components of chemigation valves. 

Many chemigation valves also have a 4-inch inspection port through which a person can reach inside and determine whether or not the check valve is still functional. If hazardous chemicals are to be injected, some governments require the use of two chemigation valves installed in series.


Double check valve

A double-check valve, also known as a double-check assembly (DCA), is a backflow prevention device that keeps water supplies clean. It differs from the two-way check valves used in heavy truck air brake systems, which select from the highest pressure source.

This uses two operating principles: first, one check valve will continue functioning even if the other is completely open. Second, closing one valve reduces the pressure differential across the other, allowing for a more reliable seal and preventing minor leakage.


Pressure vacuum breaker

A backflow prevention device such as a pressure vacuum breaker (PVB) prevents non-potable (or contaminated) water from entering the water supply. A PVB is similar to an atmospheric vacuum breaker but has a spring-loaded poppet. This makes it suitable for high-risk applications or where valves are located downstream. 

Pressure vacuum breakers require anti-freezing protection when installed outdoors. Test cocks with correctly calibrated gauges are frequently provided on PVBs to ensure proper operation.

You can pick the backflow prevention device that best shields your home from back pressure and siphonage in consultation with your plumber. One of our primary goals is to keep your home’s water supply clean.

Average Backflow Testing Cost

It is nearly impossible to provide an average backflow testing cost across the United States. 
We’ve seen prices of $65 for an annual backflow testing cost of $300. According to our experience, the average system test cost will be in the $100-$150 range. Numerous factors influence this cost.

Why Is Backflow Testing Needed?

Backflow preventer testing aims to first identify the presence of a backflow issue before fixing it. In order to conduct proper testing, you typically need to turn off your water supply temporarily.

A trusted team of professionals should install a backflow prevention device to protect against backflow in standing structures. If there is an unexpected or dramatic change in water pressure, the device will prevent backflow from entering the clean water supply system. 

However, as previously stated, it is critical that this device be properly installed by a professional so that it can be tested and ensure that the clean water line remains contaminant free. This is crucial.

While personal standards and responsibilities should maintain certain routine testing requirements, municipal codes require these backflow prevention devices to be tested annually. This ensures that they are in proper working order and that no hazardous contaminants are leaching into the clean water supply.

If, on the other hand, testing of any device is not completed on time, the water supply to a property or business may be interrupted, and the property owner may face fines. To avoid this, you should recommend scheduling a backflow test ahead of time. Also, regular backflow testing can give you peace of mind that your drinking water is free of contaminants like bacteria, viruses, parasites, and heavy metals.


The thought of how badly a backflow problem could affect you and your surroundings should be terrifying. The danger factor is extremely high.

But, thankfully, keeping your backflow prevention device in good working order can prevent all of this from happening. The major benefit of backflow testing is that it prevents what could be a major, life-changing problem for many people.

Having your annual backflow test performed not only keeps your property’s water clean but also contributes to the safety and health of your community. Let’s look at a few of the benefits:

1. Disease prevention

Sewer backups cause many of the problems associated with backflow. This backflow introduces feces and coliform bacteria into the clean water supply, significantly increasing the risk of contracting a severe infection.

Disease outbreaks such as dysentery, typhoid, and salmonella have all occurred due to fecal contamination caused by backflow.

Other dangerous bacteria are frequently found in sewage. Giardia, Campylobacter, Shigella, and norovirus are toxic bacteria that can cause gastrointestinal sickness. They can cause flu-like symptoms such as muscle aches, fevers, nausea, and vomiting.

2. Heavy metal contamination 

This can also occur due to backflow. However, this is more likely to occur in public places such as restaurants, where, for example, carbonated water can dissolve the copper in soda dispensers and lead to copper poisoning.

Heavy metals used in metal platings, such as arsenic, chromium, or lead, could also leach into the water and backflow and cause illness in commercial businesses or at home.

3. Chemical contamination prevention

Chemical waste products like insecticides, herbicides, and compounds like sodium hydroxide can enter plumbing systems through backflow. These chemicals can endanger human health once they enter the plumbing system.

4. Resist structural damage

As water flows backward, it collides with the surrounding structures, putting them under additional pressure. It can result in harm, such as rusting. 

As a result, backflow testing is critical to keeping the walls intact and free of moisture, and the backflow testing cost will help you in the long run to avoid multiple issues that you might face if you do not take prevention seriously.

What Should You Do If Backflow Is Suspected?

Knowing what to do if you find backflow in your system is critical, but don’t worry!

You just need to locate the water valve to stop water flow into your home. This will help you separate your water system and identify the location of the backflow. 

The test has two main goals: to see if there is backflow and to figure out what is causing it so that it can be fixed. The gate and relief valves on the backflow testing device are used in the testing process.

The plumber will essentially be closing valves and looking for changes in gauge movement, water leaks, and other obvious signs.

During the testing process, there are specific criteria that must be met:

  • Ensure that the check valves do not allow backflow.
  • Ensure that the airports open when they are supposed to.
  • Ensure that the relief valves open before the pressure between the check valves falls below a certain threshold.

So that the pressure between the check valves doesn’t drop below the pressure at the inlet device before the relief valves open.

A property owner doesn’t need to take any special action to prepare for a backflow test. However, they can simplify their lives and expedite the process by informing everyone concerned that the water will be turned off for a period and that they must prepare alternative water use strategies or complete the necessary activities beforehand.

Keep an eye out for these things:

  • Discolored water tastes bad
  • Smells strongly of sulfur
  • Flows slowly or is halted
  • Drains slowly
  • Contains sediments or rust particles

How Are Tests Carried Out?

The test has two main objectives: looking for backflow and pinpointing the issue causing it so it can be fixed. The backflow testing device’s “gate” and “relief” valves are used during the testing process. 

The plumber will open and shut these valves while he keeps an eye out for any changes in gauge movement, water leaks, or other red flags.

Wrapping Up

The health and safety of homeowners and everyone in the community depends on backflow testing. It also aids in environmental protection. 

Homeowners and building owners should employ the aid of a qualified plumber to ensure that the necessary backflow testing and maintenance regimen is followed. It also aids in environmental protection.

So, If you have a backflow preventer or want to install one, ensure that your new system is working correctly, and you can pay for a test. This includes a plumber moving (clean) water in the wrong direction through your system to test the backflow preventer’s functionality, usually between $20 and $100. However, the backflow testing cost depends entirely on your area.

By performing a thorough backflow test, you can take excellent care of your health and your house!

Michael Bowen

Michael Bowen

Michael Bowen is an ambitious entrepreneur who has been in the business of building homes since he was 19. Michael's commitment to honesty, integrity, and high-quality workmanship has earned him a reputation as one of the best in the business.

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