Heating, cooling and plumbing in Gainesville, from Lake Manassas to Heritage Hunt.
Most Gainesville homes went up after 2000, around a 1990s lake neighborhood and a 55-and-over village. What we find in them, what it costs, who signs off.
- Prices in writing, first
- Dedicated HVAC and plumbing teams
- Virginia license #2705192276
Get your price in writing
Two building booms, a lake neighborhood and a 55-and-over village.
A 20155 address covers everything from a 1990s lakeside street to houses finished last year, and the decade yours went up tells us a lot before we open a panel.
The 2000s and 2010s streets are most of Gainesville. In the part of 20155 the Census Bureau counts as Gainesville, about four in ten owner homes were built in the 2000s and about four in ten in 2010 or later, a third of all homes are townhouses, and gas heats about eight in ten. So the usual pair is a gas furnace and a gas water heater, and the date on their labels decides most calls.
Virginia Oaks is the older side. Its association’s guidelines go back to 1994, and its 561 homes sit on more than 170 acres of woods and meadow beside Lake Manassas, the City of Manassas reservoir. A house from that decade is usually on its second furnace and air conditioner, and the earliest date from the last years polybutylene supply pipe was in use.
Heritage Hunt is a gated community for residents 55 and older, zoned in 1997, with 1,863 homes, attached and detached, four condominiums among them. It sits outside the line the Census draws around Gainesville, so the figures above don’t describe it. Its earliest houses are 25 years old or more, and in the condominiums the association’s documents say who owns what runs through the building.
Heat, cooling and pipes, under one phone number.
Our HVAC crew and our plumbing crew are separate teams, both working out of the shop on Lafayette Center Drive in Chantilly.
Heating
Gas furnaces carry most Gainesville homes through the winter. One that came with a 2000s house is near or past 20, when inducer motors and control boards start to go, so a big repair gets a replacement price beside it. Prince William County wants a permit for a new gas furnace and none for a repair.
Cooling
A system installed before 2010 usually runs R-22, which hasn’t been made since 2020; one from a 2010s house runs R-410A. The plate on the condenser says which, and it decides whether a leak is a repair or a decision. Duct cleaning and dryer vent cleaning have pages of their own.
Plumbing
Copper or PEX supply lines and PVC drains in most houses, with a pressure reducing valve by the meter that Prince William Water leaves to you. Original tanks from the 2000s are past their years, and the water heater estimator prices a new one with the county permit counted.
One price book from Virginia Oaks to Heritage Hunt.
A Gainesville address doesn’t move the number, and you get it in writing before anybody 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
Every row comes from the price book behind our plumbing page and our AC repair page. Pricing a new water heater? The water heater estimator gives yours with the permit already in it.
Weighing a new furnace, heat pump or air conditioner? The HVAC estimator shows the installed range for a house your size before anyone visits.
Prince William County signs off, and two sources fill your pipes.
Your water
Prince William Water serves Gainesville a blend: Potomac River water treated at Fairfax Water’s Corbalis plant, and Lake Manassas water from the City of Manassas plant, which sells it 5 million gallons a day for western Prince William. The lake water alone is soft, but the utility rates the blend that reaches you moderately hard, enough to leave sediment in a tank water heater every year.
Reports: Prince William Water, 2.6 to 10.5 gpg.
Your permit office
Gainesville is unincorporated, so Prince William County issues every permit. A gas furnace or gas water heater takes one each time it’s replaced, like for like or not. An electric tank swapped for the same size in the same spot, an air conditioner or heat pump swapped for the same type in the same spot, and a repair made with replacement parts take none.
Permit pages: Prince William County.
Your sewer
On Prince William Water’s sewer, the lateral from your house out to the main needs the utility’s own repair or replacement permit and its inspection before anyone digs. Wastewater from western Prince William runs to the Upper Occoquan Service Authority’s plant, built in 1978 in western Fairfax County.
Sources: Prince William Water’s Utility Standards Manual and Prince William Water on where wastewater goes.
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 20155, from the lakeshore to the battlefield’s edge.
By the lake: Virginia Oaks, on the Lake Manassas shore. Past the I-66 exit: Heritage Hunt, beside the Conway Robinson State Forest and Manassas National Battlefield Park. Everywhere between: the 2000s and 2010s neighborhoods that make up most of the ZIP. Next door:
Questions we hear in Gainesville.
Is Heritage Hunt part of Gainesville?
For mail, yes: the homeowners’ association’s address is 13451 Fieldstone Way, Gainesville, VA 20155, and the community is in unincorporated Prince William County, so the county issues its permits. The Census Bureau’s Gainesville is a smaller area that leaves Heritage Hunt out, which is why its homes aren’t in the housing figures on our Gainesville pages.
Where does Gainesville’s tap water come from?
Two places at once. Prince William Water says western Prince William gets a blend of Potomac River water, treated at Fairfax Water’s Corbalis plant, and Lake Manassas water, treated by the City of Manassas. Lake Manassas water alone is soft, about 2.7 grains per gallon in the City’s 2025 report, but the blend that reaches you is rated moderately hard.
Do I need a permit to replace a water heater in Gainesville?
For a gas one, always, from Prince William County. An electric tank replaced with the same size in the same spot needs none. Trading a tank for a gas tankless takes a gas permit, plus electrical and plumbing permits if a circuit is added or the water lines run more than 10 feet further. The water heater estimator puts the permit in the price.
Does Virginia Oaks need an application to replace an air conditioner?
Not for a straight replacement. The association’s design guidelines list a replaced exterior air conditioner, attic ventilators and metal flues among the changes that need no application, as long as roof vents and flues stay on the back of the roof or the side least seen from the street. The county needs no permit for a same-type condenser in the same spot either.
What does an AC repair cost in Gainesville?
A run capacitor is $240 to $370, refrigerant topped up $190 to $740, and a blocked condensate drain cleared $175 to $420, from the same book we use everywhere. On a 2000s system still running R-22, a leak is where the repair-or-replace talk starts.
Lake house, townhouse or Heritage Hunt villa, call us.
Tell us your neighborhood and about when the house was built. We’ll say what’s typical for homes 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 Gainesville, Manassas, Centreville and Chantilly. 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 Gainesville, 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 20155.
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.