A plumber in Dumfries.
Plumbing in Dumfries, in the Town, Montclair and Southbridge: leaks, drains, sewer lines and water heaters, priced from our published list first.
Drain cleaning for one fixture is $200 to $800 and toilet repair is $250 to $900, from our published price list.
- Prices in writing, first
- Camera before any dig
- Dedicated plumbing team
Get your plumbing job priced
Some Dumfries lots still drain to a septic tank, and the Town wants them on the sewer once they fail.
Prince William Water runs the water and the sewer for the Town of Dumfries, though the Town’s own utility list still calls it the Prince William County Service Authority and sends sewer line leaks its way. What goes down a Town drain travels north along Route 1 to the utility’s Mooney treatment plant, pushed along by lift stations on the way.
Not every lot is on that line. The Town’s comprehensive plan says a number of septic systems in and around the Town predate the sewer, and its policy is to tie a system into the sewer once it shows signs of failing. On a septic lot a slow drain can be the tank, the drainfield or the pipe between them. SwiftPro does no septic work, so the tank and the field are a septic company’s; the pipes inside the house are ours.
The houses decide the pipe. About one Town home in ten went up before 1960 and four in ten before 1980, so galvanized supply and cast iron drains still turn up on the older single-family streets like Tripoli Heights and Whitehaven. The townhouse rows came later: Town records put Williamstown at 1974 to 1991, Port O’Dumfries at 1974 to 1988 and South Cove at 1988 to 1992, right through the polybutylene years, and the single-family Knolls of Dumfries at 1985 to 1999.
Inside the town limits, bigger plumbing jobs go on the Town’s own residential plumbing permit, not the county’s. It lists a water service line, a building sewer by the 100 feet, a pressure reducing valve and a backwater valve each on its own line. A pressure reducing valve replacement runs $500 to $1,000 on our list.
What’s in the walls across Dumfries.
Census figures for each place, and the pipe that usually goes with houses that age. Median year built and heat count owner-occupied homes only.
| Place | Median home built | Most homes are | Heated with | The pipe you usually find |
|---|---|---|---|---|
| Montclair | 1989 | single-family houses, about 8 in 10 | electricity, about 5 in 10 | The polybutylene years: check the supply pipe; PVC drains. |
| Cherry Hill | 2005 | townhouses, about 4 in 10 | gas, about 7 in 10 | Copper or PEX supply, PVC drains, original water heaters aging out. |
| Dumfries | 1985 | townhouses, about 4 in 10 | electricity, about 5 in 10 | The polybutylene years: check the supply pipe; PVC drains. |
Dumfries houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
The Town of Dumfries
Nearly all of the Town sits in 22026, with a sliver in Triangle’s 22172. None of it is in 22025.
- Median home built1985 Census
- Built before 1980about 4 in 10 Census
- Built since 2000about 1 in 10 Census
- Most homes aretownhouses, about 4 in 10 Census
- Heated withelectricity, about 5 in 10 Census
- Rentedabout 2 in 10 Census
- A lot of houses here went up while polybutylene supply pipe was in use, about 1978 to 1995, and it fails at the fittings.
- Townhouses share walls, so a leak can start on either side of one; the meter test tells you whether it’s yours.
The Prince William County side
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.
What a plumber costs in Dumfries.
The same list as our plumbing page, every line a range because the house decides where it lands. You get the number before the work starts.
- Drain cleaning, one fixture$200 to $800
- Main sewer line cleaning$550 to $1,650
- Sewer camera inspection, added to a visit$89
- Leak detection$200 to $500
- Toilet repair$250 to $900
- Pressure reducing valve replacement$500 to $1,000
- Water heater replacement$2,757 to $10,486
A sewer camera inspection is $89 added to a visit we’re already making. It’s the cheapest way to know what a drain is doing before anybody talks about digging.
With Comfort+ membership, any service is 15% off, and a water heater flush with a sewer camera inspection and a plumbing safety inspection comes every year.
What a plumbing problem in Dumfries usually looks like.
Wet ground over the drainfield
On a septic lot, soggy grass or a smell over the drainfield means the field isn’t taking water. The Town’s plan lists the usual reasons: poor soils, a high water table, tree roots in the lines, and a tank that went past its five years without a pump-out. It also says a failing system should be connected to the public sewer.
Grey plastic pipe near the water heater
Polybutylene, often stamped PB, went into houses from about 1978 to 1995. It tends to let go at the fittings with no warning, so it’s worth knowing whether you have it.
Water where it shouldn’t be
A damp patch on a ceiling, a warm spot on the floor, a meter that keeps ticking with every tap off. A slow leak inside a wall does most of its damage before it ever shows itself.
A drain that keeps coming back
One slow sink is a sink. Two slow drains on different floors are sharing the pipe out to the street, and a basement drain that gurgles while you run water upstairs is the main line talking.
After a storm in Dumfries, check the basement drains.
Heavy rain finds the weak spots in a house’s plumbing. Four checks you can make yourself, then call us and we’ll look at the rest.
Water coming up a floor drain?
Clear water with no smell is usually groundwater. Gray water, or a sewer smell, means the main line is backing up: stop running water in the house and call us.
Drains slow or gurgling since the rain?
A main line with a cracked joint or roots in it can take in groundwater during a storm and slow down. A sewer camera inspection, $89 added to a visit, shows where.
Is the sump pump running?
If the house has one, watch it once: it should start as the pit fills, empty it and shut off. Our sump pump replacement page has the rest of the checks.
Did water reach the water heater?
If floodwater got to a gas water heater’s burner or controls, leave it off. Don’t relight it until a plumber has checked it.
Call us after a storm and we’ll check it all: the floor drains, the main line, the sump pump and the water heater. Any repair gets its price in writing before the work starts.
Who owns what under the street in Dumfries.
Town of Dumfries
Inside the town limits, a building sewer, new or repaired, goes on the Town’s own residential plumbing permit, figured by each 100 feet of pipe. Source.
The Town’s residential plumbing permit gives a pressure reducing valve a line of its own, counted per valve, next to lines for a water service and a backwater valve. Source.
Prince William County
Prince William Water requires its own Lateral Repair or Replacement Permit, and its inspection, before anyone repairs or replaces a sewer lateral outside the house. Source.
Prince William Water says the pressure reducing valve is the homeowner’s to install and keep up, that the plumbing code recommends one where pressure runs 80 psi or more, and that pressure rises with the height difference between your house and the water tank serving it. Source.
How to pick the best plumber in Dumfries.
Questions worth asking anybody who comes out, us included.
Can they tell a septic backup from a sewer backup?
In Dumfries that’s the first question. On the sewer, a main line backup is a cleaning and a camera job; on septic, the same gurgle and the same slow tub can mean a full tank. A plumber who feeds a cable toward a septic tank without asking which you have has skipped a step.
Is the plumber licensed in Virginia?
Anyone can check on the state’s license lookup in about a minute. It’s the one question that takes the guesswork out of the rest.
Will they put a camera in before they talk about digging?
A sewer camera inspection is cheap next to any dig, and it shows whether the problem is a root, a sag or a break. A quote to dig without one is a guess.
Do you get the price before the work?
Every plumbing job on our list has a range. A plumber who won’t say where yours lands until the wall’s open is asking for a blank check.
What our customers say.
Zabi helped us with a complex plumbing problem. He explained clearly the problem and gave us various repair options. He is courteous, professional and highly experienced. We recommend him!
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Plumbing questions from Dumfries.
Is my Dumfries house on the sewer or on septic?
Most of the Town is on Prince William Water’s sewer. Some older lots in and around it still have septic systems that were there before the sewer, according to the Town’s comprehensive plan. A tank lid or a drainfield in the yard settles it; so does a sewer charge on your water bill.
Does replacing a water line or a sewer line inside the Town need a permit?
Yes. The Town’s residential plumbing permit has its own lines for a water service, new, repaired or replaced, and for a building sewer, counted by each 100 feet of pipe. Outside the house, Prince William Water also wants its own lateral permit and inspection before a sewer lateral is repaired or replaced. Main sewer line cleaning runs $550 to $1,650.
Why does a basement drain back up in a downpour?
Often because rain is getting into the sewer. Prince William Water lists stormwater and groundwater leaking in through cracked lines, and sump pumps or downspouts tied in, among the causes of sewer overflows. On a night like June 26, 2025, when NOAA’s storm records show flash flooding closing roads around the Town, that extra water has to go somewhere. A backwater valve, its own line on the Town’s plumbing permit, keeps the main from pushing back into a basement drain.
How much does a plumber cost in Dumfries?
It depends on the job, and every one has a published range: drain cleaning for one fixture $200 to $800, main sewer line cleaning $550 to $1,650, leak detection $200 to $500, a pressure reducing valve replacement $500 to $1,000, toilet repair $250 to $900. A sewer camera inspection added to a visit is $89.
Plumbers in the towns next door.
- Plumbing in Woodbridge
- Plumbing in Lorton
- Plumbing in Fairfax Station
- Plumbing in Manassas
- Plumbing in Clifton
More from SwiftPro in Dumfries
Tell us what the water is doing.
Call, or book online and pick a window. You get the price before the work, and if it can wait, we’ll tell you that too.
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 884 Google reviews. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team.
SwiftPro Heating, Cooling & Plumbing, 4230 Lafayette Center Dr, Suite N, Chantilly, VA 20151, (703) 997-9757. Book online, read our reviews, or see every town we serve.