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Backflow testing in Leesburg, whether the Town or Loudoun Water sends your bill: the test, the fix if it fails, and the result in before the deadline.
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What it costs
How many devices you have and what kind they are decide the number, so there isn’t one figure that fits every house. You get one flat price per device when you book, before anyone comes out.
Yearly backflow test
One flat price per device, given when you book
Repair or rebuild after a failed test
Priced in writing before any work
New backflow preventer, installed
Priced in writing before any work
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.
The national numbers, and what moves a price up or down, are in our backflow testing cost guide.
What’s different in Leesburg
A Leesburg address doesn’t tell you whose backflow rules you’re under. The water bill does. Inside the town limits, from the Old and Historic District out to Potomac Station, the Town of Leesburg is the utility. Lansdowne shares the 20176 mail but gets its water from Loudoun Water. The Town also serves some homes past its limits, its out of town customers. The backflow program comes with the water, not the town line, so if the Town sends the bill, the June 1 date is yours.
On Town water, getting the result in is your job. The Town’s backflow page puts it on residential and commercial customers alike: the yearly results go to the Town on its own backflow device report form, by email, by mail or through its online form. Whoever presses send, a report that never arrives is your missed date, so keep what was sent and the day it went. Loudoun Water flips it: the tester fills in its test sheet or online report, and the online one lands in your inbox and the utility’s at once.
The Town’s FAQ says why the test is yearly: a backflow preventer has seals, springs and moving parts that wear. The median owner home in town dates from 1996, so where the sprinkler system is as old as the house, those parts have seen a lot of winters. Downtown is the exception. The historic district’s houses mostly date from the 1700s to the Craftsman years, long before anybody watered a lawn through buried pipe, so a device there belongs to a system someone added later.
Lansdowne runs newer: nearly nine in ten of its homes built since 2000, and close to four in ten sit in condo or apartment buildings, where the building’s fire line and its device are normally the association’s job, not yours. For the rest of Loudoun Water’s program, see backflow testing in Loudoun County.
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 |
|---|---|---|---|---|
| Leesburg | 1996 | single-family houses, about 4 in 10 | gas, about 7 in 10 | Sprinklers added by an owner, pools and hot tubs. |
| Lansdowne | 2005 | condo and apartment buildings, about 4 in 10 | gas, about 8 in 10 | Lawn sprinklers the builder put in, and their device. |
By the numbers
From the Census Bureau’s 2020 to 2024 survey, owner-occupied homes unless it says otherwise.
Inside the town limits: the Old and Historic District downtown, Exeter and Carrvale inside the bypass, Potomac Station and Edwards Landing outside it.
Lansdowne only. It’s the one Census place outside the town limits, so the farms and lots beyond it aren’t in these figures.
When it’s time
Every residential sprinkler test on Town water is due June 1, and the Town says even a system nobody plans to run has to be turned on for its test. So the tests tend to land between the spring start-up and that date. Book yours right after the start-up, so a device that fails can be fixed and passing inside its 15 days, usually before June 1 arrives.
In a newer subdivision the builder often put in the lawn sprinklers, and the backflow device with them. Nobody tells the next owner it needs a test every year until the first notice shows up.
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.
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
Residential sprinkler backflow test results are due to the Town by June 1 every year, and a device that fails needs a passing report within 15 days. Source.
On Town water, an irrigation system needs a Loudoun County plumbing permit and a backflow device tested when it’s installed and every year after, with the results sent to the Town. Source.
Loudoun Water wants testable backflow devices tested every year by a certified tester. A device that fails has 30 days from Loudoun Water’s notice to be repaired and retested, and one taken off for the winter is retested when it goes back on. 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.
They should, before the gauge goes on. The Town wants results on its own Leesburg form, and Loudoun Water has its own test sheet and online report. Someone who tests on both sides of the town limits asks whose bill you get, then fills in the form that utility takes.
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.
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Questions
Yes, as long as the system is connected. On Town water it gets turned on and tested every year, run or not. To retire it, the supply is cut and capped, the Town’s Environmental Compliance Inspector checks the work, and you sign a memorandum of understanding that it’s permanently disabled. In Lansdowne, Loudoun Water asks for a cut and a permanent cap by a certified irrigation contractor or plumber.
Start with who sends the water bill. If that doesn’t settle it, the Town’s Utilities Department keeps an interactive utility service area map on its reports and maps page, the same map it points out-of-town customers to. Inside the limits it’s the Town; most of the county side is Loudoun Water.
One flat price per device, given when you book, before anyone comes out. How many devices you have, and whether one needs a repair, is what moves it. Our cost guide has the national numbers.
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.
SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
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 Leesburg and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 1,131 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.