Clean drinking water is something most of us in Plainfield, IL, tend to take for granted. With modern plumbing systems and well-maintained infrastructure, it’s easy to assume the water flowing from your tap is always safe. But behind the scenes, there’s a silent protector at work—your RPZ (Reduced Pressure Zone) backflow preventer. This small but critical device plays a huge role in safeguarding your water supply from contamination.
If you’re a homeowner, business owner, or property manager in Plainfield, understanding how RPZ devices work—and why regular testing and maintenance are essential—isn’t just smart, it’s necessary for protecting your health and your community. Let’s dive into what RPZ backflow testing involves, why it matters, and how you can help ensure safe drinking water for your property and neighborhood.
What Is Backflow and Why Is It Dangerous?
Backflow is the unwanted reversal of water flow in a plumbing system. Instead of clean water flowing in one direction—from the municipal supply into your home—contaminated water from other sources can be pulled back into the potable water supply. This usually happens due to a sudden change in pressure, often caused by something like a burst pipe, firefighting efforts, or mainline flushing.
Backflow can introduce dangerous pollutants into the drinking water, including:
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Fertilizers and pesticides from irrigation systems
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Cleaning chemicals from industrial buildings
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Human waste from toilets or sewer lines
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Bacteria and heavy metals from commercial equipment
Even a single backflow event can pose a serious health risk. That’s why the Illinois Environmental Protection Agency (IEPA) requires backflow prevention devices on many residential and commercial plumbing systems—especially those with cross-connections to irrigation, fire suppression, or chemical systems.
Understanding RPZ Backflow Preventers
An RPZ backflow preventer is a type of valve assembly designed to protect water supplies from contamination due to backflow. It contains two independently acting check valves, along with a pressure relief valve between them. This three-valve system ensures that if pressure drops on the supply side or if one valve fails, contaminated water still cannot flow backward into the clean water line.
RPZ assemblies are required in high-risk situations, such as:
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Irrigation systems with fertilizers or chemical injectors
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Boilers
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Commercial properties
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Fire sprinkler systems
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Car washes and laundromats
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Medical facilities
In Plainfield and throughout Illinois, RPZ devices must be installed by a licensed plumber and tested annually by a certified backflow technician to remain compliant with state and local regulations.
Why RPZ Backflow Testing Matters
Protecting Public Health
Contaminants introduced through backflow aren’t always visible, but the risks are very real. For instance, a report by the CDC highlighted that nearly 50% of waterborne disease outbreaks in U.S. public water systems were linked to cross-connections and backflow issues. Proper RPZ testing ensures your system is functioning correctly and isn’t contributing to these statistics.
Ensuring Legal Compliance
Under Illinois law (Title 35: Environmental Protection, Subtitle F: Public Water Supplies), annual backflow testing is required for all RPZ assemblies. Failing to test on schedule can result in fines, loss of water service, or liability if contamination occurs. The Village of Plainfield also requires property owners to submit documentation of completed testing to local authorities each year.
Preventing Property Damage
A malfunctioning RPZ device doesn’t just endanger the water supply—it can also lead to internal plumbing problems and costly water damage. Catching issues early through routine testing helps avoid emergency repairs and protects your property’s infrastructure.
When and How Often Should RPZ Devices Be Tested?
In Plainfield, IL, RPZ backflow devices must be tested:
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Annually (once every 12 months)
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Immediately after installation
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After relocation or repair
If your system fails a test, it must be repaired and retested right away. Leto Plumbing & Heating provides certified testing services and will file the required documentation on your behalf with the local water authority.
What Happens During an RPZ Backflow Test?
RPZ testing is a straightforward process—but it requires specialized equipment and licensing. Here’s a breakdown of what happens during the test:
1. Visual Inspection
The technician checks the device for obvious signs of wear, corrosion, or improper installation.
2. Test Gauge Hookup
A calibrated test gauge is connected to ports on the RPZ assembly to monitor pressure levels.
3. Valve Testing
Each check valve and the pressure relief valve are tested individually. The goal is to verify:
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Proper closure of the check valves
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The relief valve opens at the appropriate pressure differential
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No leakage occurs under simulated backflow conditions
4. Recording Results
The technician records the results and notes whether the device passed or failed.
5. Reporting
If passed, results are submitted to the Village of Plainfield or appropriate authority. If failed, recommendations are made for repairs.
The whole process typically takes 20–30 minutes, but the peace of mind it provides is priceless.
Common RPZ Problems to Watch For
Even though RPZ devices are built for reliability, they can develop issues over time—especially if they’re exposed to weather extremes, debris, or corrosive chemicals.
Signs Your RPZ May Be Failing:
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Leaking water around the device
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Unusual noise in your plumbing system
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Low water pressure throughout your building
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Failure to pass the annual test
The good news? Many problems can be resolved with a professional cleaning or valve replacement. That’s why yearly inspections are so important.
Prevention Tips for Maintaining RPZ Devices
Beyond professional testing, there are a few proactive steps you can take to protect your RPZ backflow preventer and extend its lifespan.
1. Insulate Outdoor Assemblies
Cold Illinois winters can cause RPZ assemblies to freeze and crack. Use an insulated cover, or install them in a heated enclosure.
2. Keep the Area Clear
Don’t block access to your backflow preventer with landscaping, mulch, or debris. Easy access makes inspections and repairs simpler.
3. Schedule Timely Maintenance
Stick to your annual testing schedule. Leto Plumbing & Heating can set you up with yearly reminders, so you never miss a deadline.
4. Watch for Visible Leaks
If you notice water pooling around the unit or dripping from the relief valve, call a professional immediately. Even small leaks can signal big problems.
RPZ Backflow Requirements in Plainfield, IL
The Village of Plainfield enforces strict backflow protection rules in accordance with IEPA guidelines. All commercial properties—and many residential homes with irrigation systems—must:
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Install an approved RPZ assembly at each applicable cross-connection
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Submit annual test results performed by a licensed backflow tester
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Make repairs promptly after a failed test
These requirements are in place not just for compliance, but for the health and safety of the entire community.
For residents in Plainfield, it’s not uncommon to receive annual notifications from the local water utility reminding you to schedule your backflow test. It’s a small effort with a big impact.
Why Work with a Certified RPZ Tester?
Backflow testing isn’t a DIY job. Certified testers are trained to evaluate pressure levels, calibrate equipment, and identify issues that the untrained eye might miss. When you hire a licensed professional, you ensure:
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Accurate testing and diagnostics
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Proper documentation for local compliance
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Timely repairs and part replacements if needed
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Peace of mind that your drinking water is protected
Leto Plumbing & Heating employs experienced, certified testers familiar with Plainfield regulations and equipped with the latest tools to handle your RPZ testing efficiently and thoroughly.
The Role of RPZ in Commercial vs. Residential Properties
While both residential and commercial properties in Plainfield may need backflow protection, the complexity and risk level can differ significantly.
Residential Properties
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Typically need RPZ devices for lawn irrigation systems
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Risk factors include fertilizer injection systems or pool connections
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Usually just one or two RPZ devices per property
Commercial Properties
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May require multiple RPZ assemblies for fire suppression, HVAC, manufacturing, or medical equipment
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Often subject to stricter oversight and testing protocols
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Devices may be larger and more complex
Regardless of the type of property, staying compliant with annual testing and local code is key to avoiding issues.
For RPZ Backflow Services in Plainfield, IL, Contact Leto Plumbing & Heating Today
Safe drinking water isn’t just a luxury—it’s a responsibility. Whether you’re managing a commercial facility or maintaining your family home, your RPZ backflow preventer is a frontline defense against water contamination. Keeping it in working order through regular testing and maintenance is essential.
At Leto Plumbing & Heating, we specialize in RPZ backflow testing, installation, and repairs throughout Plainfield, IL. Our licensed technicians understand local codes and are committed to protecting your water supply and your peace of mind. We handle everything—from testing and documentation to repairs and compliance support.
Don’t wait for a problem to arise. Schedule your annual RPZ backflow test with Leto Plumbing & Heating today and take the first step toward a safer, healthier home or business.








