Weak shower upstairs, strong sink downstairs
In an older Greenbriar house that can point at rusty pipe, not the valve. A new valve wouldn’t fix it. The gauge shows the difference before anyone writes a quote.
Chantilly, Virginia
Water pressure and pressure reducing valve replacement in Chantilly.
In Chantilly, 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 Chantilly are rated 5.0 stars across 1,130 reviews and work under Virginia Class A contractor license 2705192276. We cover water pressure and PRV replacement in Chantilly, Greenbriar and South Riding: which utility, how old the house, and what the gauge reads. 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.
- A gauge reading before the price
- Our own licensed plumbers
- Set and tested before we leave
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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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What it costs
What a pressure reducing valve costs in Chantilly.
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 Chantilly
In Chantilly, a gauge sorts a 1970 Greenbriar house from a 2006 South Riding townhouse.
Greenbriar’s typical owner home dates to 1970. A house that old may have no reducing valve at all, or one that’s been replaced twice, and a shower that barely runs upstairs there is more often old steel pipe narrowed by rust inside than the valve. The reading tells them apart. Good pressure at the hose bib with a weak upstairs shower is the pipe talking, and a new valve won’t help it.
Most of Chantilly proper went up in the 1980s and 90s, and six in ten homes are detached. Fairfax Water commits only to a minimum at its main and no uniform pressure across the system, and the valve on your side of the meter is yours. So two neighbors can read differently. A house down in the valley of Flatlick Branch near Walney Road generally reads higher than one on the rise above it, because lower ground adds pressure. A rule of thumb, not a number for your street.
South Riding is on Loudoun Water, whose rules also leave the regulator to the customer, and the valves there are still in their first twenty years. Those call for a reading, not a replacement, until the gauge says otherwise. Same Chantilly mailing address, two utilities: the name on your bill decides who to call about pressure on the street.
In a 1990s Chantilly house with a finished basement, the valve and main shutoff often sit in the furnace room or behind a drywall access panel. Find them on a quiet day. If a previous owner already replaced the valve, look for a small tank on the water heater’s cold line. A new valve without that tank is a common reason a relief valve starts to drip.
Neighborhood by neighborhood
What a pressure problem looks like across Chantilly.
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 |
|---|---|---|---|---|
| South Riding | 2006 | single-family houses, about 5 in 10 | gas, about 8 in 10 | A reducing valve and an expansion tank. |
| Chantilly | 1987 | single-family houses, about 6 in 10 | gas, about 5 in 10 | The builder’s original reducing valve, worn. |
By the numbers
Chantilly houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
20151, the Fairfax County side
- Median home built1987 Census
- Built before 1980about 2 in 10 Census
- Built since 2000about 2 in 10 Census
- Most homes aresingle-family houses, about 6 in 10 Census
- Heated withgas, about 5 in 10 Census
- Rentedabout 2 in 10 Census
- Houses from the 80s and 90s often came with a valve after the main shutoff, and many of those are original and worn.
- Most homes here are detached houses, each with its own meter and its own valve, usually in the basement or crawlspace where the line comes in.
20152, the South Riding side
- Median home built2006 Census
- Built before 1980hardly any Census
- Built since 2000about 8 in 10 Census
- Most homes aresingle-family houses, about 5 in 10 Census
- Heated withgas, about 8 in 10 Census
- Rentedabout 2 in 10 Census
- Houses built since 2000 usually have a valve and an expansion tank already, so the job is more often a worn valve than a missing one.
- Many homes here are townhouses or condos. A townhouse usually has its own valve near the meter; in a condo building it may be the building’s, so the association is the first call.
The signs
When a Chantilly house has a pressure problem.
The house is old enough that the valve is too
Many houses built on public water since the 1980s came with a valve right after the main shutoff. A lot of those are the originals, and a valve that old has usually stopped holding the pressure where it was set.
Pipes bang when a faucet shuts
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.
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Choosing who fixes it
How to pick who fixes water pressure in Chantilly.
Questions to ask anybody who quotes you a valve, us included.
Will they tell you whether it’s the valve or the pipe?
In a house from 1970, low pressure upstairs is often the pipe. A plumber who reads the gauge before quoting a valve is telling you what the part can and can’t fix.
Did they put a gauge on it before the price?
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.
Did they ask about the water heater?
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.
From our Google reviews
What our customers say.
5.0 stars across 1,130 reviews. Read them on our reviews page.
Arrived within an hour on a Sunday morning and provided great service.
Called SwiftPro around 5 am and their electronic system scheduled an appointment for us same day.
Polite, courteous, professional, and without any hard sell pressures.
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Where we work
Water pressure and pressure reducing valves in every Northern Virginia town we serve
Next door to Chantilly: Centreville, Herndon, Aldie, Oakton and Reston.
Fairfax County
Arlington County
Loudoun County
Prince William County
Fauquier County
Stafford County
Every town on one page
Questions
Water pressure questions from Chantilly.
Whose is the reducing valve in my Chantilly house, the water company’s?
Yours, on either utility. Fairfax Water and Loudoun Water both leave the reducing valve to the owner, on the house side of the meter. Pressure on the street is the utility’s to look into, and the valve is not.
Do South Riding townhouses share one pressure valve?
Usually each unit has its own line and its own valve, but check your documents, since a few buildings are fed through one. We can tell you which you have when we find the main.
How much is a pressure reducing valve replacement in Chantilly?
$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.
What should my water pressure be?
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
Find out what the pressure really is.
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 Chantilly 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.