Sewer camera inspection in Annandale.

The typical owner’s house in the Annandale Census place went up in 1967, and more than a quarter of its homes predate 1960. Across Annandale, Wakefield and Woodburn, about 8 in 10 were built before 1980. Many may still drain through the pipe the builder laid. Cast iron, clay tile and, on some postwar houses, Orangeburg, a fiber pipe soaked in tar, all look alike from inside the house. The camera is how you learn which one runs under the lawn.

West of the Beltway, the Wakefield Chapel area between Little River Turnpike and Braddock Road is almost entirely single-family houses, Canterbury Woods among them, and nearly 9 in 10 Wakefield homes predate 1980. Fifty-odd years is plenty of time for trees to find the line: Fairfax County’s wastewater office says roots get into open joints and cracks and can break the pipe over time. The footage shows whether they sit at one joint, which periodic cutting may hold off, or run the whole length, where the county’s other answer, new plastic pipe, comes in.

Your part of the line doesn’t stop at the curb. It runs to the county sewer, connection included, often out under the street, and replacing a stretch under a state road takes a VDOT permit on top of the county plumbing permit. The locator marks where the trouble sits, so a root-packed joint by the foundation and a broken pipe under the pavement get priced as the different jobs they are.

Not every Annandale address has a lateral of its own. About one home in five is in an apartment or condo building, 3 in 10 in Woodburn, and a line serving a whole building is the association’s call. In the townhouse rows north of Braddock Road east of Wakefield Chapel Road, check the HOA documents before you book.