A plumber in Paeonian Springs.

Where your water comes from changes the first plumbing question. If you’re on Loudoun Water, its 2025 report prints no hardness figure and sends customers to Fairfax Water’s Corbalis data. A county brochure says about a quarter of Loudoun residents, mostly in the western and northern parts, depend on groundwater, most of them on a private well on their own lot. On a well, what’s in the water varies from one well to the next, and a test tells you. We ask which you have before we quote anything.

Under Loudoun Water’s rules the pressure regulator is entirely the customer’s. It sits where the water line enters the house and wears with age, and on a house from the 1997 median it may be nearly three decades old. When it lets pressure creep up, you hear a knock in the walls when a faucet shuts, or a hiss at a supply line. Replacing it is $500 to $1,000. On a well, a pump and pressure tank set the pressure instead, and that is a different check.

The sewer side has its own split. In Loudoun the homeowner maintains the building sewer, Loudoun Water alone repairs the part under the street, and one of its inspectors checks any replacement before it is backfilled. A camera at $89 with another job, or $500 to $1,700 alone, shows which stretch has the trouble. If a trench is the answer, digging a sewer runs $7,500 to $9,000. We don’t work on septic tanks or wells.

Cold is the other plumbing story. The Purcellville station counts more than a hundred nights a year at or below freezing, Loudoun’s building code lists a frost depth of 24 inches, and late January 2026 brought Extreme Cold Warnings. A pipe in an outside wall or a crawlspace can freeze, and a leak you can’t see gets found with a locator at $200 to $500 before a wall is opened. About one owner home in six predates 1960, and old steel supply pipe in one may be due a repipe at $1,000 to $12,000.