Heating, cooling and plumbing in Haymarket, from the crossroads to the mountain.
A Haymarket address can be the 1990s town, a 2000s golf neighborhood or a 1970s house on Bull Run Mountain. Here’s what’s inside, the prices and the permits.
- Prices in writing, first
- Dedicated HVAC and plumbing teams
- Virginia license #2705192276
Get your price in writing
Three ages of house share one Haymarket ZIP.
The Town is a small piece of 20169. Most Haymarket mail goes to newer neighborhoods in the county around it, and the oldest houses sit up on the mountain.
Inside the Town of Haymarket, a crossroads chartered in 1799 and burned in 1862, very little standing is that old. The Census puts the town’s median owner home at 1995, with close to six in ten homes built in the 1980s and 90s and about a third of them townhouses. Gas heats about six in ten, electricity nearly all the rest, and a good share of the supply pipe went in during the polybutylene years.
Dominion Valley, Piedmont and the rest of the county side hold nearly all of Haymarket’s homes. Across the whole ZIP the median owner home dates to 2006 and close to half of all homes went up in the 2000s, about three in four of them single-family houses. The furnaces, condensers and water heaters their builders put in are now at the age when they start to give out.
Bull Run Mountain Estates and Evergreen are another kind of place: the median house in Bull Run Mountain Estates is from 1978, oil and electricity each heat about four in ten of them, and propane about one in eight. Water there comes from Prince William Water’s own wells or from a private well, and the utility rates its well water hard.
Furnaces, condensers and pipes, town side or county side.
Heating and cooling techs on one team, plumbers on another, all sent out from our Chantilly shop on Lafayette Center Drive.
Heating
Inside the town the gas company is Columbia Gas of Virginia, not Washington Gas, which changes the rates and the rebates on a new furnace. Up on the mountain the heat is more often oil or electric than gas, so tell us which when you call; we work on heat pumps and gas and propane furnaces, not oil burners. Our Haymarket furnace repair page lists what the usual fixes cost.
Cooling
The whole Town of Haymarket is a historic district, and its design guidelines want outdoor AC units in view of the street screened by a wall, a fence or planting. A repair touches none of that. Separate Haymarket pages cover AC repair, duct cleaning and dryer vent cleaning.
Plumbing
The Town and Dominion Valley both buy their water from Prince William Water, and the pressure reducing valve on your incoming water line is yours to keep up. Bull Run Mountain runs on wells. For a new tank, the water heater estimator gives an installed number that already counts the permit.
One price book for the Town and Dominion Valley alike.
Prices don’t change from the town limits to the mountain, and the number is in writing before anyone starts.
- AC run capacitor replaced$240 to $370
- Refrigerant topped up$190 to $740
- Condensate drain cleared$175 to $420
- Repair diagnostic visitabout $99
- Drain cleaning, one fixture$200 to $800
- Main sewer line cleaning$850 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
The figures here come from the same list that runs our plumbing page and AC repair page. Need a new water heater? Put your tank into the water heater estimator, and the price it returns has the permit built in.
Thinking about replacing a furnace, heat pump or air conditioner? Start with the HVAC estimator: give it the house size and it returns an installed range before anyone comes out.
The County permits, the Town zones, Prince William Water pipes it in.
Your water
Prince William Water serves the Town and Dominion Valley from its western supply, which mixes Potomac River water treated by Fairfax Water at Corbalis with Lake Manassas water treated by the City of Manassas, and rates it moderately hard. Bull Run Mountain Estates and Evergreen run on a separate set of six wells the utility rates hard, 7 to 10.5 grains per gallon, and some neighbors there pump from wells of their own.
Reports: Prince William Water, 2.6 to 10.5 gpg.
Your permit office
Prince William County, on both sides of the town line. The Town gave the County its building department in January 2018, but inside the town the Town’s Zoning Approval comes before the County application, and outside changes in view of the street go to its Architectural Review Board. Swapping a gas furnace or a gas water heater always takes a County permit, matching model or not; trading an electric unit for the same kind in the same place takes none.
Permit pages: Prince William County.
Your sewer, or your septic
Prince William Water wants its own Lateral Repair or Replacement Permit before anyone works on a sewer lateral outside the house, and the lines on private property are the owner’s. A house on septic falls under County Code 23-48, which sets five years as the longest a tank may go between pump-outs.
Sources: the Town of Haymarket’s building and zoning page and Prince William Water’s Utility Standards Manual and Prince William County Code 23-48.
How Northern Virginia homeowners rate us.
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.
All of 20169, inside the town line and out.
Inside the town: the streets around Washington Street and the old crossroads. On the county side: Dominion Valley, Piedmont, Bull Run Mountain Estates and Evergreen. Next door:
Questions we hear from Haymarket.
Is Dominion Valley part of the Town of Haymarket?
No. Dominion Valley, Piedmont and Bull Run Mountain Estates all carry the 20169 ZIP but lie outside the town, in unincorporated Prince William County, and the town itself holds only about one in eighteen of the ZIP’s owner homes. Prince William Water does count Dominion Valley as part of its Haymarket water system, and SwiftPro charges the same prices on both sides of the line.
Who issues building permits in the Town of Haymarket?
Prince William County, since the Town handed over its building department on January 15, 2018. Before the County application, the Town issues its own Zoning Approval, and because the whole town is a historic district, its Architectural Review Board looks at changes the street can see. Interior work and routine maintenance are exempt from that review.
How hard is the water in Haymarket?
On the system that serves the Town and Dominion Valley, Prince William Water calls it moderately hard, and its 2025 tests at the points where water enters its systems ran from 2.6 up to 10.5 grains a gallon, utility-wide. On Bull Run Mountain and at Evergreen, where the utility pumps from wells, it’s rated hard, 7 to 10.5. Hard or moderately hard, it leaves scale in a tank, so a yearly flush earns its keep.
Can a new AC condenser go anywhere inside the Town of Haymarket?
Think about the street first. The Town’s historic district guidelines ask for outdoor heating and AC units to be screened from public view by a wall, a fence or planting. A repair changes nothing outside, so the Town has no say in it. Replacing an AC or heat pump with the same kind in the same place is on Prince William County’s no-permit list.
What does an AC repair cost in Haymarket?
From our Northern Virginia price book: $240 to $370 for a new run capacitor, $190 to $740 to top up refrigerant, $175 to $420 to clear a blocked condensate drain. If your Dominion Valley house still runs its original 2000s system, find out whether it uses R-22 before paying for refrigerant.
Inside the town or up the mountain, call us.
Tell us your street, and whether you’re on Prince William Water or a well. We’ll say what’s typical for houses like yours, what it usually 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 Haymarket, Gainesville, Aldie and Manassas. 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 Haymarket, 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, inside the Town of Haymarket and across the Prince William County side of 20169.
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.