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In Ashburn, a pressure reducing valve replaced is $500 to $1,000. 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 Ashburn are rated 5.0 stars across 1,130 reviews and work under Virginia Class A contractor license 2705192276. Water pressure and PRV replacement in Ashburn, Brambleton and Broadlands, where most reducing valves are the builder’s originals and turning 20. If the pressure is fine and the trouble is a hidden leak, finding it is $200 to $500. A main shutoff valve is priced at your house, once we’ve seen the pipe it’s on.
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New copper supply piping with red-handled shutoff valves, installed and tagged by one of our plumbers.
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Licensed and insuredVirginia Class A contractor #2705192276
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What it costs
From the same price book as our plumbing price list: the valve, the fittings, setting it with a gauge and checking the house afterward. More on what causes it in our low water pressure guide.
Pressure reducing valve replacement
$500 to $1,000
Leak detection
$200 to $500
Prices checked .
Where you land in the range is mostly where the valve sits and what it’s attached to: a valve right at the main shutoff in an open basement is the easy end, one behind a finished wall or on corroded pipe is the other.
When a new valve brings the pressure down, the water heater can no longer push its expansion back into the street, so we check for an expansion tank on the same visit and tell you if the house needs one.
What’s different in Ashburn
Half the owner homes across Ashburn, Brambleton and Broadlands went up in 1998 or later, and almost every one of them came with a reducing valve the day it was built. That means a whole town’s worth of valves bought in the same few years and wearing out on about the same clock. A valve that’s been holding back street pressure for twenty years usually doesn’t quit all at once. It drifts, a few psi a year, until the house is running well above where the builder set it.
In a townhouse, finding it is half the job. Nearly four in ten Ashburn homes are townhouses, and the water line in a lot of them comes up in a utility closet under the stairs, behind the water heater, or in the garage wall of a front-load unit. If you can’t put your hand on the main shutoff and the valve beside it, that’s worth fixing before the night you need it. In a condo building, the valve may serve the whole building and belong to the association.
Loudoun Water’s rules leave the regulator to you, so nobody from the utility replaces it when it fails. What we do first is screw a gauge onto an outside hose bib and read it twice, with everything off and again with a shower running, so you see your own number. When the valve is shot, the reading can climb past what the builder set by morning, after the water heater has warmed a full tank overnight.
Most houses built here since 2000 also have an expansion tank on the water heater’s cold line. It does its job only as long as the air charge inside it holds, and many from the original build have quietly lost theirs. A worn valve and a dead expansion tank together are what make a relief valve drip and a washer’s fill valve fail early, so we test both on the same visit.
Neighborhood by neighborhood
Census figures for the owner-occupied homes in each place, and what usually sits at the main shutoff in houses like them.
| Place | Median home built | Most homes are | Heated with | What’s usually at the main shutoff |
|---|---|---|---|---|
| Ashburn | 1998 | single-family houses, about 4 in 10 | gas, about 8 in 10 | The builder’s original reducing valve, worn. |
| Brambleton | 2011 | townhouses, about 5 in 10 | gas, about 8 in 10 | A reducing valve and an expansion tank. |
| Broadlands | 2004 | single-family houses, about 6 in 10 | gas, about 9 in 10 | A reducing valve and an expansion tank. |
| Loudoun Valley Estates | 2013 | townhouses, about 6 in 10 | gas, about 8 in 10 | A reducing valve and an expansion tank. |
| Belmont | 2005 | single-family houses, about 6 in 10 | gas, about 9 in 10 | A reducing valve and an expansion tank. |
| Moorefield | 2015 | townhouses, about 6 in 10 | gas, about 7 in 10 | A reducing valve and an expansion tank. |
| One Loudoun | 2015 | townhouses, about 4 in 10 | gas, about 7 in 10 | A reducing valve and an expansion tank. |
| University Center | 1996 | condo and apartment buildings, about 4 in 10 | gas, about 8 in 10 | The builder’s original reducing valve, worn. |
By the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
The signs
In a 2005 Brambleton kitchen, the thin supply to the fridge is usually the first thing pressure finds. A second failed ice maker line or washer hose in a year is a reason to read the pressure, not just replace the hose again.
A thud in the wall when the washer or a faucet closes is water hammer, and high pressure makes it worse. So does a toilet that keeps refilling, or faucets that drip no matter how many washers go in.
When every faucet in the house went weak at once, the valve at the main is the first suspect. They wear out and can fail closed, and a stuck valve feels exactly like the water company turned you down.
Need water pressure and pressure reducing valves in Ashburn?
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Choosing who fixes it
Questions to ask anybody who quotes you a valve, us included.
In an Ashburn house from the 2000s, a new valve on a dead expansion tank still leaves the relief valve dripping. The plumber who taps the tank and checks its charge is the one who fixes it once.
A valve quoted without a pressure reading is a guess. Ask what the house reads now, static and with water running, and what they’ll set it to.
A new valve changes how the water heater handles expansion. The plumber who checks for an expansion tank is the one who saves you a dripping relief valve next month.
Two of our crew going over a work order before the day's calls.
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Questions
Usually right after the main shutoff, where the water line comes in: a utility closet, under the stairs, behind the water heater, or low in the garage wall. It’s a bell-shaped brass valve with a bolt on top.
It may be. A valve that old is often still the original, and many have drifted by then. A gauge reading tells you in two minutes whether it’s still holding.
$500 to $1,000, with the valve, the fittings and setting it with a gauge in that number. Where you land depends on where the valve sits and the pipe it’s on.
Most houses run well somewhere around 50 to 70 psi. The Virginia Residential Code calls for a reducing valve once the street pressure tops 80 psi. We read it with a gauge on a hose bib so you know your own number.
Ready when you are
Call, or send the form at the top. We put a gauge on the house, show you the number, and you get the price in writing before any valve comes out.
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 Ashburn 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.