A faucet that drips whatever you do
When a kitchen faucet drips again a month after new washers, or a toilet in the basement bath fills with a hiss, the cause is often a valve that has let pressure creep up. Read it before you replace another part.
Oakton, Virginia
Water pressure and pressure reducing valve replacement in Oakton.
In Oakton, 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 Oakton are rated 5.0 stars across 1,130 reviews and work under Virginia Class A contractor license 2705192276. Water pressure and PRV replacement in Oakton, where nearly every house has a basement and the valve is usually the first thing you see past the main shutoff. 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 Oakton.
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 Oakton
Oakton’s reducing valve sits in the basement, and most are from the 1980s.
Six Oakton homes in ten are detached, and almost every house in 22124 has a basement. That is good news for a pressure problem: the line comes through the foundation wall near the meter, and the shutoff and the bell-shaped brass valve beside it are usually on the wall, unfinished, where a gauge can go right on. When the valve is behind a finished rec room wall, that’s where the price moves.
Nearly half the homes here went up between 1980 and 1999, with a median owner house from 1984, so the typical Oakton valve is a builder’s original close to forty years old. Another 37 percent predate 1980, and those may have no valve, or one added in a later remodel. The few built since 2000 have a valve and an expansion tank, and the tank is the part people forget.
Fairfax Water promises 20 psi at the main and no even pressure past it, and the valve on the house side belongs to you. Oakton drops toward Difficult Run, with Vale Road and Waples Mill Road running along low ground that has flooded in storms, and a house down in that valley will usually read higher at the main than one up along Chain Bridge Road. Same utility, different gauge.
The townhouse subdivisions, Concord Village, Arrowood, Oakton Village and Oak Marr Courts, have their basements too, with the valve at the front of the unit by the water heater. Condo buildings like Four Winds and Treebrooke are different: ask the association before you call anybody. Your own house’s weak spot is the old kitchen faucet that drips no matter how often the washer is changed.
Neighborhood by neighborhood
What a pressure problem looks like across Oakton.
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 |
|---|---|---|---|---|
| Oakton | 1981 | single-family houses, about 4 in 10 | gas, about 6 in 10 | The builder’s original reducing valve, worn. |
| Difficult Run | 1982 | single-family houses, nearly all | gas, about 6 in 10 | The builder’s original reducing valve, worn. |
By the numbers
Oakton houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
Oakton
ZIP 22124 as a whole: every Oakton address. The Oakton Census place in the table also takes in streets with Vienna and Fairfax mail.
- Median home built1984 Census
- Built before 1980about 4 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 1 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.
The signs
When a Oakton 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.
Need water pressure and pressure reducing valves in Oakton?
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Choosing who fixes it
How to pick who fixes water pressure in Oakton.
Questions to ask anybody who quotes you a valve, us included.
Will they look at the valve before they cut the wall?
If the valve is in a finished basement, a good plumber reads the pressure at the hose bib first, and tells you whether the wall has to open at all.
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.
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What our customers say.
5.0 stars across 1,130 reviews. Read them on our reviews page.
Polite, courteous, professional, and without any hard sell pressures.
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Questions
Water pressure questions from Oakton.
Where is the pressure reducing valve in my Oakton house?
In a basement house, look where the water line comes through the foundation wall. The valve is the brass bell-shaped fitting just past the main shutoff, often by the water heater.
My Oakton house was built in 1984. Should I replace the valve?
If it’s the original, it has had a long run. Put a gauge on a hose bib with everything off; if it reads well above where it should, replace it before it fails.
How much is a pressure reducing valve replacement in Oakton?
$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 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.