How the drains connect
Every fixture in the house drains through its own branch into a main drain, which leaves the house as the sewer lateral and runs to the city sewer. In many Fullerton tract homes built in the 1950s through the 1970s, those lines run under a concrete slab, and the lateral is often cast iron or clay.
A clog in the kitchen branch only affects the kitchen. A clog in the main line affects everything upstream of it, and the lowest fixtures, usually a tub, shower or floor drain, show it first. Tree roots growing into an older clay or cast-iron lateral are a frequent cause of main line trouble.
Kitchen branch or main line
| Sign | Kitchen branch clog | Main line clog |
|---|---|---|
| Which drains are slow | Kitchen sink and dishwasher only | Several fixtures, often the lowest first |
| Toilet behavior | Normal | Gurgles or rises when other water runs |
| Running the washer | No effect on other drains | Water may appear in a tub or shower |
| Sewage visible | No | Possible in tubs, showers or floor drains |
| Outdoor cleanout | Normal | May show standing water if you can safely check |
A simple test
Only do this if no sewage is visible anywhere.
Run the kitchen faucet
Let it run for a minute while someone watches the nearest tub or shower drain.
Flush a toilet
Watch the kitchen sink and the tub. Water rising elsewhere points to the main line.
Stop at the first sign
If any fixture rises, stop the test and stop using water.
Example: it looked like a kitchen clog
Illustrative example. Not a real job or customer.
In a 1960s slab home, the kitchen sink is slow on a Sunday. By evening, the guest tub has an inch of gray water after the dishwasher runs.
- The family stops using water and keeps the kids out of the bathroom.
- A licensed plumber clears the main line through the outdoor cleanout.
- The cable brings back root fibers, so the plumber recommends a camera inspection of the lateral.
The kitchen line was fine. The real problem was roots in the lateral, which needed a different repair plan.
Ask the plumber
- Will you clear from the kitchen or from a main line cleanout, and why?
- Did the cable bring back grease, roots or something else?
- Is a camera inspection of the lateral worthwhile here?
- Which section of the lateral is my responsibility? (Check with the city.)
Common questions
Can a kitchen grease clog cause a main line backup?
Grease that travels past the kitchen branch can build up in the main line too, especially in older pipe. It often combines with roots or other debris.
Where is the cleanout on a Fullerton home?
Many homes have an outdoor cleanout near the foundation, often on the side facing the street. Some older homes have none or only an indoor one. A plumber can locate it.
Who is responsible for the sewer lateral?
Responsibility for the line between the house and the public sewer varies. Check with the City of Fullerton.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.