A plumber in Lorton.

Septic is a real part of plumbing in Lorton: the county health department holds septic permits on over a thousand Lorton parcels. Roughly half sit on Mason Neck, on streets like River Drive, Gunston Road and Belmont Boulevard; most of the rest are on Old Colchester Road or the bigger lots off Ox, Hooes and Lorton Roads. The townhouse streets are on county sewer. So the first thing we ask on a Lorton drain call is which one you have, because it changes what a backup means and whose job the fix is.

On septic, the county splits it at the foundation: a problem inside the house is a licensed plumber’s, and everything from the tank outward belongs to a septic contractor the county licenses. A slow drain in one bathroom is ours. When everything slows at once, we clear the line from the cleanout and put a camera in it, $89 added to the visit, so you know whether the pipe to the tank or the tank itself is the trouble before you book a pump truck.

Newington is the older end of town: median home 1981, and about half its homes built before 1980. A house from the 1970s usually drains through cast iron inside the walls, which rusts thin along the bottom where the water runs, while the early 1980s houses fall in the polybutylene years for supply pipe. Either way, a sewer camera inspection of the main line and a glance at the supply line leaving the water heater tell you most of what you need, and our polybutylene guide covers what replacing grey PB involves.

Laurel Hill’s houses are this century’s, mostly PEX or copper supply with PVC drains, and their trouble is younger: original water heaters past their years, shutoff valves nobody has turned since the closing, and the pressure reducing valve the builder put in by the main. Lorton’s tap water is Fairfax Water’s, most of it treated at the Griffith plant on the Occoquan, and it tested 3 to 8 grains per gallon in 2025, enough to crust a showerhead or a faucet aerator in a year or two.