The letter looks official because it is. Fairfax Water, Loudoun Water, Prince William Water, and the town utilities across Northern Virginia all send some version of it every year: your backflow preventer is due for its annual test, and there’s a deadline attached. If it just landed in your mailbox, here’s the honest summary: you’re not in trouble, this is routine, and it’s usually over in about 30 minutes.
Why Virginia makes you do this
Water is supposed to move one direction, from the utility’s main into your house. But when pressure drops suddenly, say a water main breaks or a hydrant gets opened down the street, water can siphon backward. If that happens, whatever is sitting in your irrigation lines, your pool plumbing, or a building’s fire line can get pulled into the drinking water supply. Lawn chemicals and fertilizer are the classic example, which is why in-ground sprinkler systems are the most common reason a homeowner gets one of these notices.
The backflow preventer is the mechanical device that blocks that reversal, and Virginia’s waterworks regulations require every testable one to be tested three times in its life at minimum: when it’s installed, after any repair, and once every year. The annual notice is your utility doing what the state requires of them.
One more rule worth knowing: since January 1, 2023, Virginia only accepts test reports from testers who hold the DPOR Backflow Prevention Device Worker certification. A test from anyone else is void and has to be redone.
What the test actually involves
It’s a short visit, and most of it happens at the device.
- The tester connects a calibrated gauge to the test ports on your assembly.
- Your water gets shut off for a few minutes while the gauge readings check each valve inside the device: the check valves that block reverse flow, and on RPZ models, the relief valve that dumps water rather than let anything pass.
- Pass, and the paperwork gets filed with your water authority. In Fairfax County, the testing company files it with the county within 14 days of the test. You keep a copy.
- Fail, and the device needs repair or replacement, then a retest. Most failures are rebuildable on the spot: worn springs, debris caught in a seat, or freeze damage.
The deadlines, utility by utility
Every program comes from the same state regulation, but the paperwork and the clocks differ a little depending on who sends your water bill.
- Fairfax Water + Fairfax County: a joint program. Annual testing on irrigation, fire suppression, pools, and other testable assemblies. Testers have to be DPOR-certified and on the county’s authorized vendor list, and they file your report for you.
- Loudoun Water: annual testing, and the notice means it. A failed device has 30 days to be repaired and retested. If your irrigation backflow gets removed for winterization, it has to be retested when it’s reinstalled.
- Prince William Water: annual notices when your device comes due. On the county code side, every lawn irrigation system needs a backflow device, and if you winterize with antifreeze, an RPZ is the only approved type.
- Virginia American Water (Alexandria): annual tests, reported through BSI Online. The small non-testable dual checks on homes are on a 5-year inspect-or-replace cycle.
- Town of Leesburg: the one with a calendar date. Residential irrigation results are due by June 1 every year, and a failed device needs a passing report within 15 days.
- City of Manassas: annual testing at minimum, city approval before an irrigation system goes in, and device internals overhauled every 5 years.
And the exception: Arlington County handles inspections itself. Commercial buildings get checked by county inspectors, and residential irrigation only requires the initial inspection when the system is installed. If you live in Arlington, nobody should be selling you a mandatory annual test.
What happens if you ignore it
The notices escalate, and the endpoint is the same everywhere: the utility can disconnect your water service until the device is tested and passing. Fairfax Water literally has a form letter titled “Notice of Disconnection of Water Service for a Cross-Connection Violation.” Nobody gets there by accident; it takes ignoring several letters. But the test that prevents all of it is one of the smallest plumbing jobs there is, which is why letting it slide is such a bad trade.
Why devices fail their test
Around here, the biggest culprit is winter. The PVB on a home sprinkler system sits above ground, and if the system wasn’t drained in the fall, trapped water freezes, expands, and cracks the device from the inside. It’ll still look fine from the yard. The gauge finds it in about a minute.
The rest of the failures are ordinary wear: check springs lose tension, a bit of grit holds a valve off its seat, seals age out. Most of that is rebuildable with a kit rather than a full replacement, which is worth asking about before anyone quotes you a brand-new assembly.
If you’re installing, not just testing
New sprinkler system, pool line, or fire service? The device type matters. A PVB is the standard for most home irrigation. An RPZ is the high-protection option that commercial, medical, and other high-hazard connections require, and the only option for antifreeze-winterized irrigation in Prince William County. Double check assemblies cover certain lower-hazard and fire lines where the county allows them. Permits and placement rules vary by county, so this is a job for a licensed plumber who installs to your specific code, not a landscaping add-on.
What it costs
Testing sits at the inexpensive end of plumbing work, and any company doing it right will quote you a flat per-device price before anyone drives out. The real money question is the other direction: a cracked device that gets caught in October costs a rebuild kit or a replacement, while an ignored notice ends with a shutoff, an emergency call, and the same repair anyway. Early is cheaper. It almost always is.
The short version
- The notice is routine. Virginia requires an annual test on every testable backflow preventer.
- Only a DPOR-certified tester counts.
- The test takes about 30 minutes, and the water is only off for a few of them.
- Failed devices run on short clocks: 30 days in Loudoun, 15 in Leesburg.
- Skip your fall winterization and the freeze will probably fail next year’s test for you.
SwiftPro handles backflow testing, repair, replacement, and new installation across Northern Virginia, and we take care of the paperwork with your water authority. If a notice is sitting on your counter, call (703) 997-9757, book online, or read more about how we do it on our backflow service page. One visit, tested, filed, done for the year.
