What Backflow Actually Is and Why It Matters
Under normal conditions, water flows one direction — into your home. A sudden pressure drop in the municipal main, from firefighting activity or a major break nearby, can occasionally reverse that flow, pulling water back from your plumbing toward the public system. If that reversed flow pulls from a source connected to fertilizer, irrigation chemicals, or even just stagnant water sitting in a hose, it can introduce contamination into the drinking water supply — for your property and potentially your neighbors' as well.
Where Prevention Devices Are Required
Irrigation systems, fire sprinkler systems, and certain commercial connections are the most common places Arlington requires a backflow prevention device, since these represent the highest contamination risk points in a typical property's plumbing.
Annual Testing: What's Involved and Why It's Required
Backflow preventers contain internal check valves and seals that can degrade or fail over time without any visible external sign. Testing confirms the device still functions correctly before it's actually needed in an emergency, not after.
What the Test Involves
A certified tester connects gauges to the device and checks that each internal check valve holds pressure correctly under test conditions, typically completing within 30–60 minutes for a standard residential or light commercial device.
Reporting Requirements
Test results generally need to be submitted to the local water authority to remain in compliance — a step many property owners aren't aware of until their existing device is already overdue, which is why we handle the reporting as part of the service, not as a separate task left to you.
If a Backflow Preventer Fails Its Test
A failed test isn't the end of the world, but it does mean the device needs attention before it can be certified compliant again.
Common Causes of Failure
Worn internal seals, debris caught in a check valve preventing a full seal, or a stuck relief valve are the most frequent causes of a failed test on an otherwise structurally sound device.
Repair vs. Replacement
Many failures are resolved with an internal rebuild kit replacing worn seals and springs. Devices that are very old or have a cracked housing typically need full replacement instead — we'll tell you honestly which situation applies rather than defaulting to the more expensive option.
Re-Testing
Once repaired, the device is retested to confirm it now passes before results are submitted — usually completed the same visit if parts are on hand, which they typically are for common device models.
Winterizing Irrigation Backflow Preventers
Irrigation backflow preventers are often mounted above ground for accessibility and testing, which makes them one of the more freeze-vulnerable components of a home's water system each winter. Shutting off the irrigation system's water supply, opening test cocks to relieve pressure, and draining remaining water from the device body all reduce the risk of a freeze crack forming — foam covers help but shouldn't be relied on alone during extended hard freezes.
Ready to Schedule?
Licensed, upfront, and available 24/7. Call (571) 202-6461 or request a free quote online.
Frequently Asked Questions
Does every home need a backflow preventer?
Not necessarily — it depends on what's connected to your water system, particularly irrigation, fire suppression, or certain commercial fixtures.
What happens if I skip annual testing?
Non-compliance can result in water service being restricted for the irrigation connection until testing is completed and reported to the water authority.
Who is qualified to perform backflow testing?
A certified backflow tester — we hold this certification in-house rather than subcontracting it out.
Does a failed test mean my water was actually contaminated?
No — a failed test means the device isn't currently providing reliable protection, not that contamination has already occurred.
What happens if I skip winterization and the device freezes?
A cracked device typically needs replacement before the irrigation system can be used again the following spring — an avoidable cost with proper fall winterization.