What is probably under your house
Homes built across Fullerton in the 1950s, 60s and 70s were mostly slab-on-grade tract houses. Their drains typically run in cast iron beneath the slab, then leave the foundation and continue as the sewer lateral, often vitrified clay or cast iron, to the public main. Some laterals have been partly replaced over the years, so one line can include more than one material.
Neither material is bad. Both served for decades. But after fifty or more years in the ground, each shows its age in predictable ways, and those patterns tell you what kind of stoppage to expect.
How each one tends to fail
Vitrified clay
- Resists corrosion from sewer gases and wastewater
- Laid in short lengths with many joints
- Older joints can loosen and let roots in
- Brittle: can crack from soil movement or heavy loads
- Sections can shift and leave offset joints
Cast iron
- Strong and quiet, with fewer joints
- Corrodes from the inside over time
- Rough, scaled interior catches paper and grease
- Can split along the bottom where water runs
- Hub joints can separate or let roots in
What the camera usually shows
| Finding | More common in | What it means for clogs |
|---|---|---|
| Root intrusion at joints | Clay | Recurring stoppages on a cycle |
| Heavy scale and tuberculation | Cast iron | Paper and grease snag; flow narrows |
| Channeling along the pipe bottom | Cast iron | Waste drops into the channel; risk of leaks under the slab |
| Cracked or broken section | Clay | Soil and roots enter; cable can catch |
| Offset joint | Both | A lip that catches solids |
| Belly or sag | Both | Standing water where waste settles |
Quick facts
- Typical era
- Postwar tract homes, 1950s to 1970s
- Under the slab
- Often cast iron
- Out to the street
- Often clay or cast iron, sometimes partly replaced
- How to know for sure
- A camera inspection from the cleanout
Ask about your pipe
- What material is the line at the cleanout, and does it change further out?
- Is the cast iron under the slab scaled, channeled or cracked?
- Where are the joints that roots have entered?
- Would cleaning harm this pipe, given its condition?
Common questions
Can I tell the material by looking at the cleanout?
Sometimes. A black or rust-colored pipe is often cast iron, a reddish-brown glazed pipe is often clay, and white or black plastic is PVC or ABS. The line beyond the cleanout can still be something else.
Is cast iron under the slab a problem by itself?
Not necessarily. Many lines still work well. A camera inspection shows whether scale, channeling or cracks are causing your stoppages.
Does clay pipe always need replacing?
No. Clay in good condition with sound joints can keep working. Replacement or lining usually comes up when roots, cracks or offsets keep causing stoppages.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.