It pops or rumbles
That’s water boiling under a layer of sediment on the bottom of the tank. A flush clears it out.
Water heater flushes and tankless descaling in Dumfries, Montclair and Southbridge. A tank flush is $99 right now, with a whole-home plumbing check.
Get your price in writing
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Rather talk now? (703) 997-9757
5.0 stars across 1,132 reviews
Two of our technicians in a customer’s basement, next to the furnace and a tank water heater.
Licensed and insuredVirginia Class A contractor #2705192276
24/7 emergency serviceOften same-day, and we will tell you honestly when we can get there.
Our own plumbers, our own trucksNobody here is a subcontractor with a magnet on the door
The price is settled before the workYou see the number in writing before anything is taken apart
What it costs
Same prices as our water heater flush page, anywhere in Northern Virginia, and you pay after the visit.
Tank water heater flush, with the plumbing check
$99, normally $199
Tankless descale, with the plumbing check
$300, regularly $350
Comfort+ membership, a water heater flush with a sewer camera inspection every year included
$199 a year
Both visits include a whole-home plumbing check: supply lines, shutoffs, a pressure reading, drains, toilets and traps.
One per household, owner-occupied homes, limited time. A leaking tank, or one that’s 15 years old, needs repair or replacement, not a flush.
More for the money: Comfort+ membership, $199 a year, includes the flush and its plumbing check every year, plus a sewer camera inspection, a dryer vent cleaning and heating and cooling maintenance visits.
What’s different in Dumfries
Prince William Water names Dumfries among the eastern Prince William households that get Occoquan Reservoir water treated at Fairfax Water’s Griffith plant. Griffith’s 2025 lab sheet put total hardness at 51 milligrams per liter in July and August and 135 to 137 in November and January, roughly 3 to 8 grains per gallon. The hard months land in heating season, when the incoming water is coldest and a tank burns longest to heat it.
Prince William Water’s own 2025 tests across all its systems ran 2.6 to 10.5 grains. At Griffith, every month tested sat above 4 grains except July and August, and 4 grains is where Navien wants a tankless without a softener descaled every year. A tank gathers the same minerals as grit on its bottom.
Every flush includes a pressure reading, and in Dumfries the reading moves with the ground. The Town climbs from sea level at the tidal flats to more than 170 feet, and its comprehensive plan puts Prince William Water’s Battery Hill tank on one of the two high points. The utility ties pressure to how far a house sits below the tank serving it, so the low streets get more of it, and high pressure keeps a tank’s relief valve and expansion tank busy.
The heaters sit all over. In the Town’s townhouse rows, built from 1974 to 1992, they’re usually in a closet on the lowest floor, so we run the hose to the laundry standpipe or fill buckets, and look over the pan while it’s empty. In Montclair, about three homes in four are single-family, median built 1989, with the tank usually in a basement or garage. Cherry Hill is newer, median 2005, which puts plenty of first tanks at the age when the anode rod deserves a look.
Neighborhood by neighborhood
Census figures for each place, and what we’d look at first on a flush there. Median year built and heat count owner-occupied homes only.
| Place | Median home built | Most homes are | Heated with | What we’d look at first |
|---|---|---|---|---|
| Montclair | 1989 | single-family houses, about 8 in 10 | electricity, about 5 in 10 | A yearly flush, and a look at the anode rod. |
| Cherry Hill | 2005 | townhouses, about 4 in 10 | gas, about 7 in 10 | Townhouses: utility rooms and closets, so we check the pan and the valves. |
| Dumfries | 1985 | townhouses, about 4 in 10 | electricity, about 5 in 10 | Townhouses: utility rooms and closets, so we check the pan and the valves. |
By the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
Nearly all of the Town sits in 22026, with a sliver in Triangle’s 22172. None of it is in 22025.
Montclair in 22025, where the Postal Service accepts Montclair as the town name; Southbridge and Cherry Hill in 22026, outside the town line.
ZIPs 22025 and 22026 as a whole: Montclair, Cherry Hill and the rest of Dumfries mail, the Town’s homes included.
When it’s due
That’s water boiling under a layer of sediment on the bottom of the tank. A flush clears it out.
Which is most houses. The drain valve at the bottom of the tank has usually never been opened.
E016 or E030 on a Navien, LC on a Rinnai. Scale in the heat exchanger is the usual reason, and a descale is the fix.
Choosing who does it
Questions worth asking anybody you call, us included.
A Dumfries house can sit far below its water tank or nearly level with it, and the gauge is how you find out which. If the number runs high, the pressure reducing valve and the expansion tank are the next two questions, and the flush visit is the cheap time to ask them.
The anode is the part that corrodes so the tank doesn’t, and the relief valve is the tank’s safety valve. A flush that skips both is just draining water.
A real descale isolates the heater at its service valves and pumps solution through the heat exchanger, then rinses it and cleans the inlet screen.
Two of our crew going over a work order before the day's calls.
From our Google reviews
5.0 stars across 1,132 reviews. Read them on our reviews page.
I am very happy with the service I received in installing my water heater. Tyson and the crew were very kind and cleaned everything up before they left. I would really recommend this company.
Where we work
Next door to Dumfries: Triangle, Quantico, Woodbridge, Lorton and Stafford.
Questions
Moderately. It’s Occoquan water from Fairfax Water’s Griffith plant, which tested about 3 to 8 grains per gallon through 2025, softest in July and August. That’s enough for a yearly tank flush, and a yearly descale on a tankless with no softener in front of it.
Yes, at the same price as in the Town: $99 right now for a tank, with the plumbing check, and $300 right now for a tankless descale, regularly $350. Both places carry a Dumfries address and sit in Prince William County.
$99 right now for a tank, normally $199, with a whole-home plumbing check. A tankless descale is $300 right now, regularly $350. Comfort+ membership, $199 a year, includes the flush every year.
Ready when you are
Call, or send the form at the top. Tell us tank or tankless, and the tech brings the right gear.
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 Dumfries and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 1,132 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.