Who sends your water bill decides a lot here. Inside the town, and on about 3,300 connections outside it, the Town of Vienna runs both the water and the sewer. Elsewhere it’s usually Fairfax Water and Fairfax County sewer, and some houses mix the two: Town water, county sewer. Either way the pipe between the main and your house is yours to keep up; the paperwork below says how each side puts it.
The Town checked every water service line in its system in 2024 and found no lead and no galvanized pipe: almost all copper, on the public side and the private one. That’s the line from the street to the house. Inside the walls is another question. About two in ten town houses went up before 1960, when supply pipe was galvanized steel, and most of the older stock drains through cast iron.
Rebuilt houses carry a quirk underground. When an old Vienna house comes down, its sewer lateral is usually capped near the property line, and the Town lets the builder reuse the piece from its main to that cap if a licensed plumber certifies it’s graded right and in like new condition. So a brand new house can sit on a decades-old stretch of sewer, and a camera, $89 added to a visit, is how you find out which you have.
Out in Wolf Trap about a third of the houses went up in the 1980s and 90s, the stretch when grey polybutylene supply pipe was going in, so it’s worth a look under a sink before a fitting decides for you. If a gauge on an outside spigot reads over 80 psi, the pressure reducing valve has quit or was never there, and replacing one runs $500 to $1,000.