Heating, cooling and plumbing in Catharpin, past where the water mains end.
Catharpin houses sit on big lots past the end of the public water and sewer lines, heated mostly by electricity and propane. A repair visit here is $99.
- Prices in writing, first
- Dedicated HVAC and plumbing teams
- Virginia license #2705192276
Get your price in writing
Single-family houses on five and ten acre lots, built in two waves.
Prince William County’s address list has about 390 homes with Catharpin addresses, every one a detached house, and all but two sit on land zoned A-1, agricultural. On the County’s land records the median lot is a little over five acres, and more than a third run to ten acres or more.
The first wave ran from the late 1960s to the mid 1970s, when the plats for Sudley Mountain (Bobwhite, Robin and Bluebird), Breezy Knoll Estates, Boxwood Farms, Olde South Estates, Catharpin Farms Estates and Richland Estates were recorded. A house that old has probably gone through three or four water heaters and at least one new heat pump or furnace. Supply pipe from the 1970s is usually copper; a house plumbed from the late 1970s into the 1990s can have gray polybutylene.
The second wave is Green Gables, recorded in 2002, Dominique Estates in 2004 and Magnolia Meadows on Catamount Court in 2019. More than a third of Catharpin’s houses, most of them along Sanders Lane, Aldie Road and Sudley Road, sit on parcels the County files under no subdivision at all. Its records put the typical house at about 2,900 square feet above ground.
Electric and propane heat most of them. Catharpin’s ZIP is too small for the Census to measure well, so these shares are for the Census tract around it, about 2,000 homes including neighbors with Gainesville, Haymarket and Manassas mail: close to four owners in ten heat with electricity, about three in ten with propane, under one in five with natural gas, and close to one in ten with oil.
Heat pumps, propane furnaces, and plumbing between a well and a septic tank.
HVAC work goes to our HVAC team and plumbing to our plumbing team, both based at the shop on Lafayette Center Drive in Chantilly.
Heating
Electric heat out here usually means a heat pump with backup strips. The weather station at Dulles Airport, about eight miles northeast, averages around a hundred nights a year at freezing or below and about five at 10 degrees or colder, and on those nights the strips carry more of the load. Propane means a furnace fed from a tank your supplier fills; when one won’t light, glance at the tank gauge before you call. Oil burners we leave to oil companies, but replacing one with a heat pump or a propane furnace is work we’ll price.
Cooling
A heat pump does the heating and the cooling, so it never gets a season off. A house of roughly 2,900 square feet may have two systems, one per floor, which means two filters and two condensate drains to keep clear. Air conditioning repair, air duct cleaning and dryer vent cleaning each have a page of their own.
Plumbing
No Prince William Water line comes within half a mile of a Catharpin house, so the water starts at your well and leaves through your septic tank. Everything between them is ours: supply lines, fixtures, the water heater, the drains. The well pump and the tank belong to well and septic contractors, and we’ll tell you plainly when that’s where the trouble sits.
Five acres or fifty, the price book doesn’t change.
A Catharpin address pays the same figures as a Chantilly townhouse, and you see yours in writing before any work starts.
- 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
Every row comes from the price book behind our plumbing page and our AC repair page. Replacing a propane or electric water heater? The water heater estimator gives the installed price with the County permit in it.
Heat pump near the end, or ready to move off oil? Give the HVAC estimator your square footage and it returns an installed range before anyone comes out.
Your well, your septic tank, and Prince William County for permits.
Your water
Catharpin sits on the Culpeper Basin, the sandstone and shale under western Prince William; one of its rock layers even carries the name Catharpin Creek Formation. A USGS study of the county’s wells found the basin’s water runs alkaline and usually carries the most dissolved minerals in the county, with the highest sulfate, from gypsum in the rock. In a water heater that means scale, and sometimes a rotten egg smell on the hot side.
Your permit office
Catharpin is unincorporated, so Prince William County issues every permit. A propane furnace or water heater is a gas appliance in the County’s eyes, so replacing one takes a permit each time, matching model or not. An electric water heater or a heat pump swapped for the same kind in the same spot takes none. Wells and septic systems are the Prince William Health District’s to permit.
Permit pages: Prince William County.
Your septic
Prince William Water runs no sewer here either, and the County’s septic layer lists 366 Catharpin parcels. The Health District keeps each system’s records and quotes County Code 23-48: pump the tank at least once every five years. When a drain backs up, a camera down the line shows whether the clog is in the pipe, which is ours, or at the tank, which isn’t.
Sources: Prince William County’s address, parcel and zoning maps and Prince William Water’s lines on the County map and the USGS study of Prince William’s wells and the Health District’s septic and well page.
What Northern Virginia homeowners, Catharpin included, say about 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). One of the 2026 neighborhoods is Aldie Road Plus, which Nextdoor files under Catharpin.
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 Catharpin lately
In the last 30 days SwiftPro’s vans worked in Gainesville, Haymarket and Centreville, the towns around Catharpin.
Catharpin is 7 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 lane in 20143, from Sudley Road to the end of Sanders Lane.
On the roads and lanes: Sudley Road, Aldie Road, Sanders Lane, Pageland Lane and Marble Hill Lane. In the subdivisions: Sudley Mountain, Breezy Knoll Estates, Boxwood Farms, Olde South Estates, Catharpin Farms Estates, Richland Estates, Green Gables, Dominique Estates and Magnolia Meadows. Next door:
Catharpin questions.
Is any of Catharpin on public water or sewer?
No. Prince William Water’s own lines, as the County maps them, don’t enter the Catharpin ZIP at all, and the closest Catharpin house is more than half a mile from one. Homes here run on private wells and septic systems, which is why the Prince William Health District, not the utility, holds their records.
Why does my hot water smell like rotten eggs?
Usually the water heater is making the smell, not the well. Water from Culpeper Basin rock can carry a lot of sulfate, and bacteria living in the tank, fed by its magnesium anode rod, turn it into hydrogen sulfide. If the cold tap smells fine and only the hot side stinks, the fix is often a different anode rod and a flush, not a new tank. If the cold smells too, get the well water tested first.
Does swapping a propane water heater take a permit here?
Yes, every time. Prince William County treats a propane water heater like any gas appliance, so even a matching tank in the same spot gets a permit. An electric tank of the same size in the same place doesn’t need one. SwiftPro’s water heater estimator builds the permit into the price.
Will SwiftPro service my oil furnace?
No, we don’t work on oil burners, so for the burner itself call an oil service company. Around Catharpin close to one owner in ten still heats with oil. When you’re ready to switch, a heat pump or a propane furnace is ours to quote and install, and the HVAC estimator gives you a range first.
Why do the taps go dry when the power goes out?
Because the well pump runs on electricity. Once the pressure tank empties, nothing comes out until the power is back. Storms out here bring big trees down: the National Weather Service logged trees down on Sanders Lane in May 2022 and numerous large trees near Sudley Springs and Catharpin in June 2020, and a falling tree can take a power line with it. Fill a few jugs when a storm is coming, and if a pipe freezes while the heat is off, shut the water off at the pressure tank and call us.
What does an AC repair cost in Catharpin?
Clearing a blocked condensate drain is $175 to $420, a new run capacitor $240 to $370, and topping up refrigerant $190 to $740, the same book we use across Northern Virginia. Since a heat pump here also heats the house, a repair in August is also a repair for January.
Sudley Road, Sanders Lane or Catamount Court, call us.
Tell us your road and what heats the house: propane, a heat pump or both. We’ll tell you what a Catharpin house that age usually needs, what 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 Catharpin, Gainesville, Haymarket and Centreville. 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 Catharpin, SwiftPro repairs and replaces heat pumps, propane and gas furnaces, air conditioners and ductless mini-splits, cleans air ducts and dryer vents, and handles plumbing from leaks and fixtures to water heaters and the drain line out to the septic tank, across 20143.
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.