Sewer pipe materials: what you have and how it fails
The year your house was built is the fastest clue to your sewer pipe, and the pipe decides which repairs will hold.
The short answer
Homes built before the 1970s usually have clay, cast iron or Orangeburg sewer laterals; most later homes have PVC or ABS plastic. Orangeburg — installed mainly from the late 1940s to the early 1970s — is the one to worry about, because it deforms and collapses. Clay and cast iron often last far longer and can frequently be lined instead of replaced.
In this section
What pipe do you probably have?
Build year narrows it quickly, but many older laterals have been partly replaced, so a camera inspection is the only way to be sure along the whole run.
How the materials compare
| Material | Typical life | How it fails | Can it be lined? |
|---|---|---|---|
| Orangeburg | 30–50 years | Softens, ovalises, blisters, collapses | Only while still round — usually replaced |
| Cast iron | 50–100 years | Scale inside, channel worn through the bottom | Often, after descaling |
| Clay | 50–100+ years | Joints crack and let roots in; brittle | Often, if round and passable |
| PVC / ABS | 50–100 years | Installation faults — bellies, bad joints | Rarely needed |
Which old pipes are worth saving
Material decides more than age. A 90-year-old clay line that still holds its shape can often be lined and last decades more, while a 55-year-old Orangeburg line that has started to flatten usually cannot be saved at any price. Cast iron sits in between: scale alone is a descaling job, but a channel worn through the bottom of the pipe means replacement.
The practical rule is to decide on footage, not on the year the house was built. Build year tells you what to look for; the camera tells you what you have. If you are buying an older house, ask about the sewer pipe as early as you ask about the roof and the furnace — replacing a lateral can cost about as much.