Signs Your Main Sewer Line Is Clogged

Everything that drains in your house — every sink, toilet, tub, shower and washing machine — ends up in one pipe that leaves the building and runs out to the street sewer. That pipe is the main line.

When a sink blocks, you lose a sink. When the main line blocks, you lose the house. And because the blockage is downstream of everything, the symptoms show up somewhere other than where you would expect, which is why people spend a weekend plunging a toilet that was never the problem.

Here is the pattern.

1. More than one fixture is affected at once

This is the one that matters most, and it is the first thing worth checking.

Run the taps in the kitchen. Flush an upstairs toilet. Run the bathroom basin. If one fixture is slow and the rest are fine, the problem is at that fixture. If several are slow or backing up at the same time, the problem is the line they all share.

Nothing else on this list is as reliable as that single test.

2. Using one fixture causes water somewhere else

This is the signature of a main line blockage, and once you have seen it you will never mistake it.

• You flush a toilet and water rises in the tub or the shower tray
• The washing machine drains and the toilet bubbles
• You run the kitchen sink and water appears at a basement floor drain

What is happening is straightforward. The water you sent down has nowhere to go, so it backs up and comes out at the lowest opening available to it. That is almost never the fixture you used.

3. Gurgling

A drain that gurgles is a drain pulling air through standing water. In a healthy system, air comes in through the vent stack that runs up through your roof and the water goes out cleanly. When the line is partially blocked, the water cannot move freely and air gets dragged back through the trap instead.

One fixture gurgling occasionally is not much. A toilet that bubbles every time the washing machine runs is a main line telling you it is running out of capacity.

4. The basement floor drain overflows

The floor drain is usually the lowest opening in the whole house, which makes it the first place a backup appears.

It is worth being precise about the direction here, because it changes the diagnosis completely:

• If water will not go down the floor drain, the floor drain may be silted up — that is a floor drain problem
• If water is coming up out of it, the floor drain is fine and is simply the exit point for a backup from the main line

In the second case, cleaning the floor drain achieves nothing. It is the messenger.

5. A smell outside, or a patch of lawn that is suspiciously good

If the line has failed rather than blocked — cracked, separated at a joint, or collapsed — waste can escape into the soil around it.

What that looks like above ground is a strip of lawn that is greener, lusher and wetter than everything around it, sometimes with a slight dip, and sometimes with a smell on warm still days. A lawn does not do that for no reason, and the reason is usually below it.

6. It has happened before

A line that blocks once is usually just blocked. A line that blocks twice in a year or two is a line with something wrong with it — roots at a joint, a section that has settled and now holds water, a crack, or a partial collapse.

Clearing it a third time will work, and it will happen again. That is the point at which running a camera down it stops being an extra and starts being the thing that stops you paying for this every spring.

What to do while you wait

Stop putting water down the drains. No dishwasher, no laundry, no long showers. Every gallon that goes in has to come out somewhere, and it will pick the spot.

Do not reach for a chemical drain cleaner. A main line blockage is tens of feet away past a lot of standing water, which dilutes the chemical long before it gets anywhere near the problem. What you end up with is a line that is still blocked and a basement full of caustic water for whoever opens it.

If you have an outside cleanout — a capped pipe sticking up near the foundation — and you know where it is, mention it when you call.

What we do about it

We clear main lines across Lodi, Garfield, Hackensack, Clifton, Paterson and the rest of Bergen and Passaic counties. If it has happened before, say so when you call — it changes what we bring and what we recommend.

Call (201) 315-6655, day or night, any day of the week.