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SwiftPro tests and repairs backflow preventers in Great Falls, and the yearly test is $250 a home (normally $300). Call SwiftPro, rated 5.0 stars across 1,130 reviews, at (703) 997-9757, 24 hours a day, 7 days a week.
SwiftPro’s plumbers in Great Falls are rated 5.0 stars across 1,130 reviews and work under Virginia Class A contractor license 2705192276. Backflow testing in Great Falls for homes on Fairfax Water: we test the device on your sprinklers, pool or yard hydrant and see the County gets the report. Book it at (703) 997-9757 or online. We’re rated 5.0 stars across 1,130 reviews, and we set the visit around the date on your notice.
5.0 stars across 1,130 reviews
Our plumbing team in front of three of our vans.
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Licensed and insuredVirginia Class A contractor #2705192276
24/7 emergency serviceWe answer day or night, and we will tell you honestly when we can get there.
Our own plumbers, our own trucksNobody here is a subcontractor with a magnet on the door
The price is settled before the workYou see the number in writing before anything is taken apart
What it costs
The yearly test is $250 a home, normally $300, and you can pay for it online. HOA and condo communities that book their units together pay $175 to $225 a unit. A new preventer, installed and tested, runs $800 to $1,200. Those are for a home’s device up to 1 inch; where an HOA unit or a new preventer lands in its range is set at the house and quoted before we start.
Yearly backflow test, one home
$250 (normally $300)
HOA or condo units booked together, per unit
$175 to $225
New backflow preventer, installed and tested
$800 to $1,200
Repair or rebuild after a failed test
Priced in writing before any work
Prices checked .
A device that fails is priced in writing before any work. Most can be rebuilt with new springs, seats or rubber parts; a body cracked by a freeze gets replaced. Either way it’s tested again afterward, which Virginia requires.
Booking for an HOA, townhouse or condo community? Here’s what each unit pays when the community books one visit. And what a backflow test costs covers what moves the price up or down.
What’s different in Great Falls
More than half of Great Falls runs on private wells. Of the 5,829 detached houses with a 22066 address, the County’s tax records list 2,532 as connected to public water and 3,211 with no public water available. The yearly test protects the public system, so it applies to houses on Fairfax Water. The quarterly water bill is the quick tell: no Fairfax Water bill, no public connection.
The rule that matters most here is about the houses that have both. A well and the public line may never be tied together, not even through a closed valve. A house that connects to Fairfax Water and wants to keep its old well for watering the lawn goes through the utility’s lawn irrigation well procedure: the well gets reclassified and disconnected from the house plumbing, the capped piping gets photographed for Fairfax Water, and a plumbing inspector signs off before the meter goes in. If you’re buying a Great Falls house that switched over, ask to see that paperwork.
The lots make the rest of it. The median detached lot in 22066 is about 1.4 acres and a third run 2 acres or more: room for a long sprinkler run, a pool, and a frost-proof hydrant out by the garden. On public water, each is a separate connection with its own device. The hydrant is the one people forget: Fairfax Water wants an RP upstream of it, a permit, and a passed test on file before it’s used.
On a big lot the device can be in the basement, where the sprinkler line leaves the house, or down by the meter near the road. If the notice lists more assemblies than you know about, start at the meter and walk the line. The Fairfax County backflow testing page covers the County’s side.
By the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
When it’s time
Houses that took public water later often kept the well for the lawn. That’s allowed only when the well is fully cut off from the house plumbing; any pipe or bypass joining the two is the cross connection the rule exists to stop.
Anything piped to the water supply that could push water back into it gets a device: lawn sprinklers, a pool fill line, a hot tub. More yard usually means more of them.
A letter from the water utility with a date on it means there’s a testable device on your line, usually on the lawn sprinklers, and its test is due.
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Before the first hard freeze
A device that sits full of water all winter is the most common reason it fails the spring test. Around here, get this done by the end of October.
On most houses it’s outside by the foundation: a brass valve on two pipes standing out of the ground, with a cap on top. That’s a PVB. An RPZ or double check may sit in a basement or a box in the ground instead.
Turn off the valve that feeds the sprinklers, usually in the basement or utility room just past the main shutoff. Leave the rest of the house on.
Most systems here get blown out with compressed air so nothing sits in the lines or the device. If yours hasn’t been, that’s the step that matters.
Set the device’s two shutoff handles and its little test cocks about halfway, near 45 degrees, so no pocket of water stays trapped inside to freeze.
An insulated cover helps a PVB through the winter. On an RPZ, never block the relief valve opening underneath: it has to be able to dump water.
Some owners bring the device inside for the winter. Check the rules first: Loudoun Water wants a device that came off tested again when it goes back on, and Fairfax County wants it back on before your testing month.
Not sure it was drained, or saw water coming from the cap when the sprinklers ran? Call us. We’ll look at it, and if it cracked, you get the reason and a price before anything gets replaced.
Who sends the notice
Fairfax County’s Cross Connection Program wants testable backflow devices on lawn sprinklers, fire sprinklers, pools and hot tubs tested every year by a tester on the County’s Authorized Vendor List. The tester files the report and the County emails you when it’s in; nothing after 14 days, and the County asks you to check with them. Source.
Each property gets its own testing month from the County’s tax map grid, and the report is due before that month ends. A device that fails has to be repaired or replaced and retested within 10 business days of the failed test, and one taken off for the winter goes back on before the testing month. Source.
Our Virginia Class A contractor license, 2705192276, is on the side of the van.
Choosing a tester
Questions to ask anybody who offers to test it, us included.
A Great Falls property on public water can carry a device for the sprinklers, one for the pool fill and an RP for a yard hydrant. Ask for one visit that tests all of them, each on its own line of the report.
Since January 1, 2023, Virginia only accepts tests from a DPOR-certified Backflow Prevention Device Worker, and some places keep a list of their own on top. Ask to see the certificate before the gauge goes on.
Some utilities take it from the tester and some want it from you. Ask which, and keep a copy either way, so you can show the date if a second notice turns up.
Ask for the reason and a written price before anything gets taken apart, and whether the retest is part of it. A failed device runs on a deadline, so a tester who can also fix it saves you a second trip.
Two of our crew going over a work order before the day's calls.
From our Google reviews
5.0 stars across 1,130 reviews. Read them on our reviews page.
Tyson was wonderful; professional, very knowledgeable, thorough and fast. He was great at telling me about what was needed, and I very much appreciated that. For the next plumbing problem we have, I will have SwiftPro on speed dial.
Questions
The County’s yearly test is for assemblies protecting the public water system, so a house on a well alone with no Fairfax Water connection isn’t who the notice is aimed at. If you got one anyway, call the number on it and ask what they have on record for your address.
Yes, through Fairfax Water’s lawn irrigation well procedure. The well is reclassified and disconnected from the house, photos of the capped piping go to the utility, and the final plumbing inspection has to pass before the meter is set. The two systems can never be connected.
SwiftPro does, all over Great Falls. We test the backflow preventer on your sprinkler system, fire line or pool in about 30 minutes, repair it on the same visit if it fails, and get the report where your water utility wants it. Call (703) 997-9757 or book online.
The yearly test is $250 a home, normally $300, and you can pay for it online. HOA and condo units booked together on one visit run $175 to $225 a unit. A new preventer, installed and tested, is $800 to $1,200. Where an HOA unit or a new preventer lands in its range is set at the house and quoted before we start, and a device that fails is quoted in writing before any repair. More in what a backflow test costs.
About 30 minutes a device. The water is off for a few of those minutes while the gauge readings are taken.
Ready when you are
Call, or send the form at the top. Have the notice handy: how many devices it lists and the date on it are what we need. Or pay $250 online and we’ll call to pick the day.
SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
SwiftPro Plumber & Water Heaters
4200 Lafayette Center Dr, Suite N, Chantilly, VA 20151
Virginia Class A contractor license #2705192276
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Great Falls and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 1,130 reviews on Google, Angi, Yelp, the BBB and Facebook. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team.
From SwiftPro Heating, Cooling & Plumbing in Chantilly. Housing figures are the Census Bureau’s American Community Survey, 2020 to 2024, for each place named; permit, water and sewer facts link to each office’s own page and were checked in September and October 2026.