If you live in Troy, Grand Rapids, or Royal Oak, you are likely already familiar with the term “backflow prevention test.” For those not in these cities or new to these areas, you might be wondering more. Backflow prevention testing has recently been trending due to Michigan’s initiatives to protect its water.
So, whether you’re learning about backflow prevention for the first time or diving deeper into its purpose, this is the guide for you. Here, we’ll cover everything you need to know, including the basic definition, the different types of prevention devices, and how testing is performed step-by-step.
Keep reading for the ultimate guide to backflow prevention testing in Michigan.
What is Backflow Prevention Testing?
Many local communities have implemented backflow testing as part of Michigan’s initiative to keep our water and the Great Lakes free of contaminants. Backflow testing is part of the statewide cross-connection control program to help prevent water contamination.
Backflow prevention testing refers to the process of checking backflow prevention devices in homes or businesses to ensure they’re working correctly. These devices are installed in water systems to prevent contaminants from flowing back into the clean water supply, hence the importance of ensuring their optimal operation.
Backflow Prevention Devices Types to Know
Before we get into the step-by-step process of what to expect from a backflow prevention test, it’s essential to know the different types of devices. The test to check them may vary depending on their type.
Double-check valves and a reduced pressure principle device are the two most common backflow prevention devices. Here’s what makes each unique:
- Double-check valves: These devices consist of two independently operating spring-loaded check valves arranged in series. They prevent the reversal of water flow by closing automatically when the pressure in the system drops, effectively creating a barrier against backflow caused by back-pressure or back-siphonage. Double-check valves are commonly installed in fire sprinkler systems, irrigation systems, and various industrial applications where there is a moderate risk of contamination. While unsuitable for high-hazard situations, they provide reliable protection in low- to medium-risk scenarios.
- Reduced pressure principle: More complex, reduced pressure principle (RPP) devices consist of two independently operating spring-loaded check valves with a pressure-differential relief valve between them. The RPP assembly creates a zone of reduced pressure that is always lower than the inlet pressure, ensuring that potentially contaminated water cannot flow back into the main supply. If either check valve fails, the relief valve opens and discharges water to maintain the pressure differential. RPP devices are highly effective and are used in high-hazard applications with a risk of toxic substances entering the water supply. They are commonly installed in chemical plants, hospitals, and other facilities with potential cross-connections.
Backflow Prevention Test: What to Expect
Backflow device prevention testing is often required annually or bi-annually in Michigan and other states. Here’s the step-by-step process to how it’s performed.
#1: Shut Down Water Supply
The plumber will shut down your water supply first to prevent any unintended water use during the test, which could impact the accuracy of results or interfere with the procedure.
#2: Visual Inspection
First, the plumber will visually inspect the device, checking for any signs of wear, damage, or tampering. This step ensures no physical issues will interfere with the testing procedure and verify if any leaks, cracks, corrosion, or missing parts are present (screws, gaskets, caps, etc.).
#3: Attach Testing Equipment
The testing equipment is then attached to the device to measure pressure and flow accurately and ensure its correct functioning. There are typically three test cocks or ports on a reduced pressure zone (RPZ) or double-check valve assembly where the equipment is attached.
#4: Perform Testing
Testing begins with the first check valve that prevents water from flowing back into the water supply. First, a pressure reading is recorded and should meet the manufacturer’s minimum acceptable pressure to pass (usually around 5 PSI)
If testing a reduced pressure zone (RPZ) device, the relief valve’s pressure will also be tested. This is crucial for releasing water when the pressure differential between the inlet and outlet drops below a set level. If the relief valve opens at a pressure higher than the minimum requirement (usually around 2 PSI), the valve is working correctly.
Finally, the second check valve will be tested, measuring the pressure differential between the two sides of the valve. A properly functioning check valve will hold pressure at the manufacturer’s recommended level (often 1 PSI or higher).
Once the testing is completed, the test ports need to be closed by shutting the valves or cocks used to measure pressure.
#5: Restore Water Supply and Retest
Next, the water supply will be restored, and the plumber will retest the system, ensuring it returns to normal operating levels after the testing. They’ll check the pressure gauges to ensure the system pressure returns to normal operating ranges without drops that could indicate a malfunction or leak.
#6: Record and Report Test Results
In many jurisdictions, backflow prevention device testing is required by law, so it’s essential to document results for compliance and future reference. The certified plumber performing your testing will record the pressure readings and any observations about the device’s condition.
This report will be provided to the property owner and the relevant water authority (if necessary). It will include whether the device passed or failed and any recommendations for maintenance or repairs.
#7: Repair or Replace (if Needed)
If any part of the backflow prevention device fails the test, immediate repair or replacement is necessary to ensure the integrity of the water system.
The Final Word Backflow Prevention Tests
Whether the city you live in requires a backflow prevention test or if you want to do your own due diligence, there’s one professional plumbing service to call upon to help: WaterWork Plumbing. For backflow prevention testing, your plumbing service will need a special certification which WaterWork has covered.
WaterWork has been serving the Metro Detroit area since 2006, after being founded by a master plumber. Growing from one truck to over 2,000 reviews (with a 4.8-star average!), we’re proud to serve the area with exemplary service and expert repairs.
Call WaterWork for all your plumbing needs, including regular maintenance, backflow testing, emergency services, and renovations. Before you go, be sure to check out our library of resources and education to keep your plumbing up to par!
