You live in town and a sprinkler came with the house
The yearly test belongs to whoever owns the house now. If the last owner kept up with it, the Town has a report on file. If not, the first test is yours to book.
Herndon, Virginia
Backflow testing in Herndon.
SwiftPro tests and repairs backflow preventers in Herndon, 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 Herndon are rated 5.0 stars across 1,130 reviews and work under Virginia Class A contractor license 2705192276. Backflow testing in Herndon: inside the town line the Town’s own Building Inspections office takes the report; in Franklin Farm and Floris it’s Fairfax County. 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.
- Yearly test $250, normally $300
- Repairs priced in writing first
- Dedicated plumbing team
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What it costs
What a backflow test costs in Herndon.
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 Herndon
Herndon runs its own backflow program, so the report goes to the Town, not the County.
Most of Northern Virginia sends backflow reports to a county office. Inside the Town of Herndon it’s the Town’s Building Inspections section that keeps the program, because the Town runs its own water. Its rule is short: every backflow device in town, lawn sprinklers included, gets tested once a year by a certified backflow tester, who fills out the Town’s own report form and emails it back to Building Inspections. Keep a copy of that report for yourself, too.
The Town Code behind it has teeth. Public Works can come inspect for cross connections, and saying no counts against you. If a device the Town requires is missing, pulled out or bypassed, the Town can shut the water off until it’s put right. That’s worth knowing before anyone takes a sprinkler device off for the winter and forgets to put it back.
Cross into Franklin Farm, Floris, McNair or the Dranesville side and the rules change, because those homes buy water from Fairfax Water and fall under the County’s program, printed below. Your water bill settles it in a second: a Town of Herndon bill means Town rules. The Town page doesn’t list a due month or say how owners get reminded, so if you’re not sure when yours is due, ask Building Inspections before the season starts.
Which houses even have a device? A third of the homes on the county side went up since 2000, and plenty of those detached lots came with a builder’s sprinkler system and the backflow device that goes with it. Inside the town most houses are older, so a device is more often one an owner added later. In the townhouse rows and the condo buildings off Sunrise Valley Drive, the association usually runs the irrigation and tests its own device. More on the County side is on our Fairfax County backflow page.
Neighborhood by neighborhood
Where the backflow devices are across Herndon.
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 |
|---|---|---|---|---|
| Franklin Farm | 1985 | single-family houses, about 9 in 10 | electricity, about 5 in 10 | Sprinklers added by an owner, pools and hot tubs. |
| Herndon | 1981 | single-family houses, about 4 in 10 | electricity, about 6 in 10 | Sprinklers added by an owner, pools and hot tubs. |
| Dranesville | 1984 | single-family houses, nearly all | electricity, about 6 in 10 | Sprinklers added by an owner, pools and hot tubs. |
| McNair | 2003 | condo and apartment buildings, about 6 in 10 | gas, about 7 in 10 | The building’s fire line, tested by the association. |
| Floris | 1990 | single-family houses, about 8 in 10 | gas, about 6 in 10 | Sprinklers added by an owner, pools and hot tubs. |
| Hutchison | 1979 | townhouses, about 5 in 10 | electricity, about 7 in 10 | Mostly the association’s sprinklers, plus any yard system an owner added. |
| Sully Square | 2015 | condo and apartment buildings, about 6 in 10 | gas, about 6 in 10 | The building’s fire line, tested by the association. |
By the numbers
Herndon houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
The Town of Herndon
Inside the town limits. Floris, Franklin Farm, McNair and Dranesville, on the Fairfax County side, are counted by the Census as places of their own.
When it’s time
When a backflow preventer in Herndon needs a tester.
The yearly notice came
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.
Water running from the relief valve
On an RPZ, a little water when the pressure jumps can be normal. A steady stream from the opening underneath means a check valve isn’t sealing, and it won’t pass.
Need backflow testing in Herndon?
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Before the first hard freeze
Before it freezes in Herndon, drain the backflow preventer.
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.
- 1
Find the device
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.
- 2
Shut the sprinkler supply
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.
- 3
Get the water out
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.
- 4
Leave the valves halfway
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.
- 5
Cover it, but not the relief port
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.
- 6
Taking it off? Ask first
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
Who sends the backflow test notice in Herndon.
Fairfax County
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
How to pick who tests your backflow preventer in Herndon.
Questions to ask anybody who offers to test it, us included.
Do they have the Town of Herndon’s report form?
The Town wants its own form, sent to Building Inspections. A tester who only knows the County’s online system may file in the wrong place.
Will the test count with your utility?
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.
Who sends the report?
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.
What happens if it fails?
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.
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What our customers say.
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Where we work
Backflow testing in every Northern Virginia town we serve
Next door to Herndon: Reston, Sterling, Great Falls, Oakton and Chantilly.
Fairfax County
Arlington County
Loudoun County
Prince William County
Fauquier County
Stafford County
Every town on one page
Questions
Backflow questions from Herndon.
Who checks backflow testing in the Town of Herndon?
The Town’s Building Inspections section, under Town Code Chapter 74. Testers return the Town’s report form to its office by email. Fairfax County’s program covers the county side, not homes on Town water.
What happens if my device fails or goes missing?
Fix it and get it retested. Town Code lets the Town cut off water where a required device is missing, removed or bypassed, until it’s corrected. The Town doesn’t post a repair deadline, so ask Building Inspections how long you have.
Who does backflow testing in Herndon?
SwiftPro does, all over Herndon. 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.
How much does a backflow test cost in Herndon?
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.
How long does a backflow test take?
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
Get the notice off the fridge.
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 Herndon 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.