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SwiftPro tests and repairs backflow preventers in Oakton, 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 Oakton are rated 5.0 stars across 1,130 reviews and work under Virginia Class A contractor license 2705192276. Backflow testing in Oakton, from the acre lots near Fox Lake to Oak Marr Courts: we test the device, fix it if it fails 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 Oakton
North of Jermantown Road and out toward Fox Lake, Oakton lots run close to an acre and most houses are on septic. Of the 4,220 detached houses with a 22124 address, the County’s tax records show 3,608 with no public sewer. People assume that means a well too, and it usually doesn’t: 3,537 of those same houses are connected to Fairfax Water. A big lawn on public water is exactly what the County’s yearly test is for, so a septic tank is no reason to ignore the notice.
Oakton grew up mostly in the 1980s and 90s, nearly half its homes from those two decades, and a lot of those half-acre and acre lots got sprinklers once the trees came in. On a lawn that size, a few owners end up feeding fertilizer through the irrigation. If anything feeds chemicals into your sprinkler water, Virginia code wants an RP on it, not the AVB or PVB a plain lawn system can use. If a lawn company ever added an injector, check what device is protecting it before your test.
About half of Oakton tests in July, going by the County’s month chart and the tax map grid most 22124 parcels sit in. That’s a good month for it: the system is on and pressurized, so the tester can run the device as it actually works. Most of the rest of the ZIP falls in December or March grids, which can land on a winterized system. Check the month on your notice and book before the end of it.
Oakton also has about 1,185 owned townhouses, at places like Oak Marr Courts and Oakborough Square, and roughly 1,170 condo units around Mosby Woods. Those owners rarely have a device of their own; the shared lawn or the building’s service line is the association’s. The Fairfax County backflow testing page covers the notice itself.
Neighborhood by neighborhood
Census figures for the owner-occupied homes in each place, and what usually brings the test notice to houses like these.
| Place | Median home built | Most homes are | Heated with | What usually needs the test |
|---|---|---|---|---|
| Oakton | 1981 | single-family houses, about 4 in 10 | gas, about 6 in 10 | Sprinklers added by an owner, pools and hot tubs. |
| Difficult Run | 1982 | single-family houses, nearly all | gas, about 6 in 10 | Sprinklers added by an owner, pools and hot tubs. |
By the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
ZIP 22124 as a whole: every Oakton address. The Oakton Census place in the table also takes in streets with Vienna and Fairfax mail.
When it’s time
Some lawn services offer feeding through the sprinklers on bigger lots. Once chemicals go into the irrigation water, the rule calls for an RP. A PVB that was fine for plain water isn’t the right device anymore.
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.
Need backflow testing in Oakton?
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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.
On an Oakton lot with a fertilizer injector or a pool fill tied in, ask the tester to confirm the device type is right for what it protects. A passing test on the wrong device is still a problem.
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.
Where we work
Next door to Oakton: Fairfax, Vienna, Reston, Dunn Loring and Annandale.
Questions
Probably not. Most Oakton houses without public sewer still get Fairfax Water: the tax records show 3,537 of 4,220 detached houses connected. Check for a quarterly Fairfax Water bill. If you have one and have sprinklers, the yearly test applies.
It depends on your tax map grid. About half of 22124 falls in July, and most of the rest in December or March. Your County notice gives the month, and the report has to be in before that month ends.
SwiftPro does, all over Oakton. 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 Oakton 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.