9 Signs Your Sewer Line Is Failing (and What to Do About It)

Quick answer: The most common signs of a failing sewer line are several slow drains at once, sewage backing up through a tub or floor drain, smells that won’t go away, gurgling toilets, soggy patches in the yard, sinking ground, and clogs that keep coming back. If you notice more than one, call a plumber.

Your sewer line is buried, so you usually don’t know it’s in trouble until something gets messy. A dripping faucet is easy to spot. A cracked pipe under the lawn is not. The pipe does tend to give hints first, though. Here’s what to watch for, what could be causing it, and what to do.

1. Several drains slow down at the same time

One slow sink is usually hair, soap, or grease. When the kitchen sink, bathroom sink, and shower all drag on the same day, the problem is likely in a shared drain or the main line.

What to do: Cut back on water use. Skip repeated rounds of chemical drain cleaner, which can be rough on older pipes. If the drains stay slow, have a plumber check whether the clog is local or in the main line.

2. Water backs up in a tub, shower, or floor drain

Flush a toilet and watch water bubble up in the shower. Run the washing machine and see the basement floor drain fill. In both cases, wastewater has nowhere to go, and it may contain sewage.

What to do: Stop using water, keep children and pets away, and don’t touch the water. Don’t keep flushing to see if it clears, because that usually makes the backup worse. Call a plumber right away.

3. A sewage smell that won’t go away

A dry drain trap, a worn toilet seal, a vent problem, or a damaged pipe can all cause sewer odors. Where the smell shows up helps narrow it down. A smell from one rarely used drain is often just a dry trap. A smell in several rooms, or out in the yard, is more suspicious.

What to do: Run water in unused drains first. If the odor returns, schedule an inspection instead of covering it up. And never climb into a sewer pit or other confined space to investigate, because sewer gases can be dangerous.

4. Toilets gurgle when other fixtures run

A toilet that burbles when the sink drains or the washing machine empties means air and water aren’t moving the way they should. A partial clog could be the cause, but so could a blocked plumbing vent, so gurgling alone doesn’t prove the sewer line is damaged.

What to do: Notice which fixtures are running when it happens and tell your plumber. If gurgling comes with slow drains or backups, book an inspection.

5. Wet spots or unusually green grass in the yard

A leaking sewer pipe can keep one patch of lawn soggy when it hasn’t rained, and the waste adds moisture and nutrients that can make grass look greener and grow faster there. Irrigation leaks, poor drainage, and broken water supply lines can look the same, so watch whether it keeps happening.

What to do: Don’t dig it up yourself, since other utility lines may be buried nearby. Have a plumber find the source. Covering the spot or re-landscaping won’t stop a leak.

6. The ground sinks near the sewer line

When a pipe cracks or separates, soil can wash into it or away from it. Over time that leaves a dip in the lawn, a sunken walkway, or even a small hole. Erosion and poorly packed fill can do the same thing.

What to do: Keep people off unstable ground and don’t fill in a deep hole before you know the cause. If it keeps sinking or sits close to the foundation, get it assessed. A structural specialist may be needed if the building itself seems to be moving.

7. Clogs keep coming back

One clog can come from grease or a stray wipe. A clog that returns a few days after it was cleared suggests something else is going on, such as tree roots, a sagging or misaligned pipe, heavy buildup, or damage inside the line. Age matters too, but an old pipe isn’t automatically a bad one.

What to do: Write down when each clog happened, what was done, and how long the fix lasted. Then ask your plumber about a camera inspection, which shows what’s actually inside the pipe.

8. Your water bill jumps for no clear reason

A sewer problem doesn’t normally make your water meter spin faster. A higher bill more often points to a running toilet, a leaking supply line, or an irrigation problem. It becomes relevant when it shows up alongside slow drains, odors, or backups.

What to do: Check toilets, faucets, and outdoor taps for leaks. Then turn off everything and see whether the meter still moves. If it does, you may have a supply-side leak. Mention every symptom to your plumber so the two systems get checked separately.

9. Cracks or other damage appear near plumbing

Floor cracks, shifting soil, or damage along the sewer route can go along with underground plumbing trouble. They can just as easily come from foundation settling or poor drainage, so they’re clues, not proof.

What to do: Take photos and note when you first saw the change. If cracks are growing or backups are also happening, call a plumber. For serious structural movement, bring in a structural engineer too.

What causes sewer line damage?

Tree roots: They slip into small cracks or loose joints, then catch debris and narrow the pipe.

Grease and wipes: Both build up inside the line and form clogs.

Aging pipes: Older materials can corrode, crack, or develop loose joints.

Shifting soil: Settling and erosion can bend a pipe or leave low spots where waste collects.

Installation problems: Poor slope, bad alignment, or past repairs can cause repeat trouble.

The cause matters because the fix depends on it. Clearing a clog won’t repair a collapsed pipe, and replacing the whole line is overkill when the problem is simple debris.

How do plumbers check a sewer line?

Expect questions first: which fixtures are affected, when it started, and what’s been done before. Next comes a look at accessible drains and the cleanout.

For repeat clogs or multiple affected drains, plumbers often run a small camera through the line to look for roots, cracks, standing water, and misaligned sections. From there, the fix could be as simple as clearing the clog, or it could be a spot repair or section replacement. Trenchless repair works for some pipes but not every kind of damage.

Before approving major work, ask what the camera showed, why this repair fits, and whether the quote covers testing and yard restoration.

How can you prevent sewer problems?

Nothing guarantees a line will never fail, but these habits help:

• Keep grease and oil out of the drain.

• Throw wipes, paper towels, and hygiene products in the trash, not the toilet.

• Treat repeat clogs as a warning, not a one-off.

• Find your sewer cleanout before you need it.

• Call before you dig or plant large trees.

• Keep records of plumbing repairs and inspections.

In Pennsylvania, freezing weather can also damage vulnerable pipes, though winter alone doesn’t mean an underground sewer line has failed.

When should you call a plumber?

Call when several drains slow down together, sewage comes up through a fixture, odors linger, clogs keep returning, or you suspect an underground leak or see ground sinking.

Homeowners in Montgomery County, Bucks County, and nearby Pennsylvania communities can reach Royal Penguin Plumbing for leaks, drainage problems, and other plumbing work. When you call, describe which fixtures are affected, whether wastewater has backed up, and what repairs have been done before. If sewage has entered your home, keep everyone away from it and avoid contact with the water.

Frequently asked questions

What is the first sign of a damaged sewer line?

Often it’s several slow drains at once. Other early signs include recurring clogs, sewage odors, gurgling toilets, and backups in low drains. Each can have other causes, so an inspection confirms what’s going on.

Can a clogged drain mean the main sewer line is blocked?

Yes, but one clogged sink or shower usually has a local cause. If multiple fixtures are affected together, a shared drain or the main line is more likely.

Does a cracked sewer pipe always need to be replaced?

No. It depends on where the crack is, how bad it is, and the pipe’s overall condition. Some damage can be repaired locally, while severely damaged sections may need replacement.

Is a sewer camera inspection worth it?

It’s helpful when clogs keep returning or the cause is unclear, since it shows the plumber the inside of the pipe before any repair is recommended.

Who pays for sewer line repairs in Pennsylvania?

Homeowners are often responsible for the private sewer lateral serving their home, but the exact boundary varies. Check with your local sewer authority before arranging major work.

The bottom line

A slow drain, a strange smell, or a wet patch of grass may have a simple explanation. But when signs stack up, or sewage starts coming back up, don’t rely on quick fixes. A professional inspection can tell you whether you have a routine clog or real damage, and catching it early usually means less mess and a cheaper repair.