Heating, cooling and plumbing in Triangle, from Graham Park to Kerill Road.
A repair visit in Triangle is $99. Half its homes went up after 2000 and a few before 1940, all beside the base at Quantico. What we find, who signs off.
- Prices in writing, first
- Dedicated HVAC and plumbing teams
- Virginia license #2705192276
Get your price in writing
About half the homes went up after 2000. One in six is older than 1960.
The Census puts Triangle’s median owner home at 2003, which hides how split the place is: a third of all its homes were built in one decade, the 2000s, while about one in sixteen went up before 1940.
Graham Park and the streets near it are the old side. County plats date Carborough Heights to 1946, Graham Park and Mockingbird Heights to 1950, Amidon to 1955 and East Graham Park to 1959, and Nob Hill, Oakdale, Graham Park Shores and Barnette Forest followed in the 1960s. Under a house from those years you can still find galvanized steel supply lines and cast iron drains, often patched with copper or PEX wherever a leak got fixed.
The 2000s subdivisions came almost all at once. Kerill Woods was platted in 2001, then Cramers Ridge, Garrison Woods, Moncure Woods, Lionsfield Valley and The Reserve at Potomac Crest in 2004. Houses finished the same year got their furnaces, condensers and water heaters the same year, so whole streets of equipment are passing twenty years old together.
Gas does the heating. About three in four owner homes burn natural gas and close to all the rest use electricity; propane and oil hardly show up. Close to four homes in ten are rented, and about three in ten sit in a building with two or more units, from duplexes to apartment blocks.
Gas furnaces, tired condensers, and pipes from two very different eras.
Heating and cooling calls go to our HVAC team, pipes and drains to our plumbing team. Both run out of the shop on Lafayette Center Drive in Chantilly.
Heating
Nearly every Triangle furnace burns gas. In the 2004 subdivisions it’s often still the builder’s unit, at the age when flame sensors, inducer motors and control boards start failing, so we’ll price a replacement next to any big repair. In Graham Park the furnace has usually been swapped a time or two already.
Cooling
The weather station at Quantico’s Marine Corps air station, about four miles away, averages close to 30 days a year at 90 degrees or hotter, and its July nights average about 71, so an air conditioner here gets little rest after dark. An original 2000s condenser most likely holds R-22, a refrigerant the United States stopped producing in 2020; read the plate before you pay to recharge one. Air conditioning repair, air duct cleaning and dryer vent cleaning each have their own page.
Plumbing
Prince William Water serves about nineteen detached houses in twenty. The exceptions cluster out Joplin Road and on Johnson and Williams Roads, past its lines. On the old streets, galvanized pipe rusts shut from the inside and shows up as weak hot water; on the new ones, the first water heater is overdue.
Graham Park, Kerill Road or a condo, the same price list.
Triangle gets the figures we charge everywhere in Northern Virginia, and you see yours in writing before anybody starts work.
- AC run capacitor replaced$240 to $370
- Refrigerant topped up$190 to $740
- Condensate drain cleared$175 to $420
- Repair diagnostic visit$99
- Drain cleaning, one fixture$200 to $800
- Main sewer line cleaning$550 to $1,650
- Leak detection$200 to $500
- Pressure reducing valve replacement$500 to $1,000
- Water heater, tank, installed$2,757 to $7,494
These come straight from the price book behind our plumbing page and our AC repair page. Pricing a new gas water heater? Our water heater estimator gives the installed number with the County permit counted.
Builder furnace and air conditioner both past twenty? The HVAC estimator shows the installed range for a house your size before we visit.
Most of Triangle is Prince William County’s to permit. One corner belongs to the Town of Dumfries.
Your water
Prince William Water, which lists Triangle among the places it fills with Occoquan Reservoir water treated at Fairfax Water’s Griffith plant. Griffith’s own 2025 tests swung with the seasons, 51 mg/L of hardness in July and August against 137 in January, but even the soft months leave scale in a tank water heater over a year.
Reports: Prince William Water, 2.6 to 10.5 gpg.
Your permit office
Triangle has no town government, so Prince William County permits nearly all of it. The exception is the slice of 22172 inside the Town of Dumfries, the Port O’Dumfries townhouses and the Townsquare Court apartments among it, where the Town’s own building department signs off. On the County side, a gas furnace or gas water heater needs a permit every time; a heat pump or condenser swapped for the same type in the same place doesn’t.
Permit pages: Prince William County or Town of Dumfries.
Your sewer, or your septic
Most of Triangle drains to Prince William Water’s sewer, and eastern Prince William’s wastewater ends up at the utility’s H.L. Mooney plant. The County’s septic layer still lists 146 parcels with Triangle addresses, mostly on Joplin, Johnson and Williams Roads, and County Code 23-48 wants each of those tanks pumped at least once in five years.
Sources: Prince William County’s address and parcel maps and the County’s septic parcel layer and Prince William Water on where wastewater goes.
What homeowners across Northern Virginia say.
5.0 stars across 884 Google reviews. Read them on our reviews page.
Voted a Nextdoor Neighborhood Faves winner two years running: 2026 in 30 Northern Virginia neighborhoods, 2025 in Emerald Chase (Herndon) and Hunters Run (Chantilly).
Listed in both the HVAC and Plumbing categories of Northern Virginia Magazine’s Best Home Experts directory, which is exactly how we’re built: a dedicated HVAC team and a dedicated plumbing team.
Our vans in Triangle lately
In the last 30 days SwiftPro’s vans did replacement quotes, heating and cooling repairs, new heating and cooling installs and plumbing repairs in Triangle, most recently on Friday, October 2.
Triangle is 26 miles from SwiftPro’s Chantilly shop, and the van that comes to you is coming from the last job, not from the shop. SwiftPro charges no distance fees anywhere it serves.
Every street with 22172 mail, off the base.
The older streets: Graham Park, East Graham Park, Graham Park Shores, Nob Hill, Oakdale, Barnette Forest, Mockingbird Heights and Amidon Avenue. The 2000s subdivisions: Kerill Woods, Cramers Ridge, Garrison Woods, Moncure Woods, Lionsfield Valley and The Reserve at Potomac Crest, with Thomasson Crossing from 1988. Out Joplin Road: the houses on the way to Prince William Forest Park’s entrance. Inside the Town of Dumfries, with Triangle mail: Port O’Dumfries and Townsquare Court. Next door:
Triangle questions.
Does SwiftPro work on base housing at Quantico?
No. Family housing aboard Marine Corps Base Quantico, 1,137 homes by the base’s count, is owned, managed and maintained by Liberty Military Housing, so a repair there goes through Liberty. We work in the off-base houses, townhouses and condos with Triangle addresses. If you rent one of those, the repair normally goes through your landlord or property manager, who can book us directly.
Is my Triangle address inside the Town of Dumfries?
It might be. On Prince William County’s address map, about one Triangle home address in eight sits inside the Town of Dumfries: the Port O’Dumfries townhouses on streets like Masthead Trail and Port Hope Point, the Townsquare Court apartments, and a few houses on Orange Street. Those take Town permits. Everything else with 22172 mail is Prince William County. Our prices are identical on both sides.
My 2004 Triangle house still has its original furnace and AC. Fix them or replace them?
Fix them if the repair is small and the house heats and cools evenly. Past twenty years, though, a cracked heat exchanger, a dead compressor or an R-22 leak is usually where replacing makes more sense, and we’ll put both prices on paper so you can compare. A run capacitor, for scale, is $240 to $370.
How hard is Triangle’s water?
Moderately hard, and it changes through the year. Fairfax Water’s Griffith plant, which treats the Occoquan water Prince William Water sends to Triangle, measured 137 mg/L of hardness in January 2025 and 51 in July. That’s roughly 3 to 8 grains per gallon. A yearly flush keeps the sediment from building up in a tank water heater.
What does an AC repair cost in Triangle?
Our book prices: $190 to $740 to top up refrigerant, $175 to $420 to clear a clogged condensate drain, $240 to $370 for a new run capacitor. They’re the same in Triangle as in Chantilly. On a 2000s system, check whether it’s R-22 before you buy refrigerant for it.
Graham Park, Kerill Road or Port O’Dumfries, call us.
Tell us your street and about when the house was built. We’ll tell you what usually wears out in a Triangle house that age, what fixing it costs, and when we can be there.
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company serving Northern Virginia, including Triangle, Dumfries, Woodbridge and Lorton. SwiftPro holds Virginia contractor license #2705192276, is a Trane Comfort Specialist, Rheem Pro Partner and Mitsubishi Diamond Contractor, holds 5.0 stars across 884 Google reviews, was voted a Nextdoor Neighborhood Faves winner two years running, for 2026 in 30 Northern Virginia neighborhoods and for 2025 in Emerald Chase (Herndon) and Hunters Run (Chantilly), and is listed in both the HVAC and Plumbing categories of Northern Virginia Magazine’s Best Home Experts directory. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team. More at goswiftpro.com.
In Triangle, SwiftPro repairs and replaces furnaces, heat pumps, air conditioners and ductless mini-splits, cleans air ducts and dryer vents, and handles plumbing from drains and leaks to water heaters and sewer lines, across 22172 outside the base.
SwiftPro Heating, Cooling & Plumbing, 4230 Lafayette Center Dr, Suite N, Chantilly, VA 20151, (703) 997-9757. Every town we serve is on the town-by-town guide.