A historic house, say anything before about 1930, has a drainage system assembled over a century by many hands. The original drain may be cast iron with lead joints, clay, or in some cities a brick or stone sewer; it will have been patched, extended and partly replaced in every decade since, and parts of it may lead to a cesspool or a storm drain that nobody remembers. The inspection of such a house is less a check than a survey, and the buyer should plan it that way.
Quick answer: inspect from every available entry and follow every drain to its end. Expect a house trap near the foundation, mixed materials, abandoned lines, and a lateral whose connection to the main may be very old. Use a smaller camera head and a flexible rod for the traps and small bores, and a sonde to map the routes. Price the findings knowing that a historic district may constrain excavation and that a brick or stone sewer section is a specialist repair. Budget for a survey, not a scope.
What is likely to be there
Cast iron drains and stacks with lead-and-oakum hubs, galvanized or lead branch lines, a clay lateral, a house trap and fresh-air inlet near the foundation wall, and in older cities a connection to a brick or stone combined sewer. Later decades added copper, Orangeburg, ABS and PVC in patches. Cesspools and dry wells that predate the public sewer may still be connected to something. Cameras for old houses covers equipment suited to this mix.
Plan the entries
Historic houses rarely have modern cleanouts. Entries are the house trap’s cleanout plugs, pulled toilets, tub and shower drains, roof vents and whatever cleanouts later plumbers added. Each gives a different section. List them before the inspector arrives and expect the inspection to take longer than a modern house. Entry options covers the trade-offs.
The house trap
A U-shaped trap on the building drain just inside or outside the foundation, with two cleanout plugs on top, was standard in many cities until the mid-twentieth century. It is a tight double bend that catches debris and stops a standard camera head. A smaller head on a flexible rod passes it; alternatively the inspector enters downstream of it from the outside cleanout plug. Note its condition; a cracked iron trap under a basement floor is a repair.
Small bores and lead
Branch lines in a historic house may be 1.5 or 2 in galvanized or lead, which a 23 mm head cannot enter. A small drain camera from a trap arm shows their condition. Lead bends under toilets and lead branch lines are a water-quality question as well as a drain one and should be noted for replacement during any renovation. Small-diameter cameras and head size for 2 in pipe cover the equipment.
Following every line
A historic house may have drains that go to a cesspool in the garden, a dry well, a storm drain or simply end. Every fixture’s drain and every pipe leaving the foundation should be followed with the camera and the sonde until it reaches the lateral or something else, and the something else should be recorded. An active cesspool is a health department matter; an abandoned one is a collapse hazard. Locating the head is how the routes are mapped.
The lateral and the connection
The lateral may be the original clay or iron with a century of joints, and the connection to the main may be into a brick sewer through an opening cut by hand. Push to the main and look at the tap. In a brick or stone combined sewer the camera will see the main’s condition too, which is the utility’s responsibility but the buyer’s exposure in a surcharge.
Previous repairs
Expect to find them and record each: a PVC section in an iron run, a liner in part of the lateral, a rubber coupling at a house trap. Each change of material is a joint to check and a clue to past problems. Verifying a known repair applies to each one found.
Historic district constraints
Where the house is in a designated district, excavation in the front yard, removal of historic paving or trees, and alterations visible from the street may need approval, which adds time and sometimes cost to a lateral replacement. Trenchless methods are often preferred for this reason. Ask the local preservation office before pricing a repair.
Pricing the survey and the work
The inspection itself costs more than a modern scope because it takes longer and needs more equipment; budget for it. Repairs range from a stack base to a full lateral in a constrained site. Get quotes from contractors who work on old houses, from the footage and the route map. Negotiating repairs covers the process.
What to record
The route map with every drain followed to its end. Materials by section. The house trap’s location and condition. Every previous repair. The lateral and the tap. Abandoned or unknown lines with their surface locations. This is the drainage survey of the house and it will be referred to for as long as the house stands.
Common questions
Do old houses have sewer cleanouts?
Often only the plugs on the house trap, and sometimes none. Pulled toilets and roof vents are the usual entries.
What is a house trap and should it be removed?
A U-bend on the building drain that was once required and is now usually removed when found, because it catches debris and blocks cameras. Many cities now prohibit new ones.
Can a camera inspect a brick sewer?
Yes, and the picture shows the mortar joints and any missing bricks. The lateral’s connection to it is the buyer’s concern; the brick main is the utility’s.
Related guides
See cast iron drain priorities, cameras for 4 in pipe, and cameras with replaceable heads.