What is Backflow Testing?

January 30, 2021

If your business in the Midwest has been asking the question, “What is backflow testing,” Mid-West Instrument is happy to provide a detailed answer. And along with analyzing your company’s backflow testing needs, we’re a trusted source for backflow kits, backflow preventers, and associated professional-grade components.

What is Backflow Testing?

The longer the pressure in a water system isn’t maintained, the greater the risk for water to flow backward into the water system and become contaminated. Backflow testing monitors the health and safety mechanisms designed to protect water purity in the Midwest.

Why it Matters

The function of backflow testing and prevention is to keep dirty water from flowing backward into pools, storm drains, and the external water sources that deliver clean, uncontaminated water into your home for drinking, bathing, and cleaning.


Business owners are required by law to have a backflow test performed annually at their premises by a certified plumbing company. The test takes about 20 – 30 minutes to complete if no repairs are needed. Valves are opened and closed to check for any irregularities, and a form is submitted to the city to confirm everything is working well and that there are no code violations.


Most home and business owners have no way of knowing whether backflow is occurring. That’s why it’s critical to schedule an annual backflow inspection with an experienced firm like Mid-West Instrument to head off any potential problems. During a backflow inspection, our team will inspect the assembly that connects your home/business to the public water supply. This assembly has valves that can become damaged, which could allow backflow to happen. Our professional inspection process will determine whether there is a problem, and if so, what steps should be taken.

Average Cost

It’s difficult to quote an average cost for backflow testing that could be considered standard across the U.S. You might see an estimate as low as $65 or one as high as $300. In our experience, a range of $100 – $150 is accurate. Bear in mind that this is only for the systems test, and there are several other factors that may need to be accounted for.

How is Testing Performed?

There are two main purposes of the test: to see if backflow is present and to determine the issue that is causing it so that it can be fixed. The testing process involves using valves on the backflow testing device known as “gate” and “relief” valves. The plumber will open and close these valves, checking for changes in gauge movement, water leaks, and other warning signs.

Types of Backflow Preventers

The most common types of backflow prevention devices are A) an air gap, which is a space in the water storage area that connects to a home/business plumbing system, and B) a check valve, which forces the water to flow in one direction instead of backward into your home.

How to Purchase Backflow Preventers for Your Plumbing Needs

Mid-West Instrument offers an extensive selection of backflow preventers for sale, and we make ordering easy. Visit our website today to familiarize yourself with our diverse product line or contact a team member who can help you source the exact item you need.