Drain cleaning in The Plains.

Only about a tenth of the homes in ZIP 20198 are inside the town itself, which makes The Plains small enough that its housing is well documented. The state’s register describes 140 properties, nearly half from 1900 to 1930 and almost a quarter from the 1940s and 1950s. A house from those decades usually has one main stack, and everything a family does with water meets there.

The Cape Cods on Loudoun Avenue date from the late 1940s, and a Cape Cod has a particular quirk: the upstairs bath tucked under the roof slope, with a drain that turns hard at the knee wall before it drops. That turn is where hair and paper stick. We clear it from the tub when we can reach it, and from the cleanout in the cellar when the clog is farther down.

The register notes that stone is commonly used in foundations and that several buildings sit into a banked site with a cellar entrance at grade. A cellar like that tends to have a laundry corner and a floor drain, and the floor drain is the lowest opening in the house. If it gurgles when the washer empties, the main run is closing, and we start there.

The 1950s brick houses on Mosby Street and the 1920s kit house are the other end of the range. A kit house shipped by rail came with a short, simple plumbing plan, one bath and one kitchen on a stack, and nothing was sized for a modern household with a dishwasher and a second shower. Add a few decades and a family that doubled in size, and a slow kitchen drain is almost a given.