Sewer Line Problems: 7 Warning Signs Every Homeowner Should Know

Your sewer lateral — the underground pipe that carries wastewater from your home to the public sewer main — is one of the most critical and least visible parts of your plumbing system. When it develops problems, the consequences range from unpleasant to catastrophic. Recognizing the warning signs early lets you address issues before they escalate into emergency backups and expensive repairs.

1. Multiple Slow Drains

When a single drain is slow, the clog is usually in that specific drain line. When multiple drains throughout the house are slow simultaneously — kitchen sink, bathroom sink, shower, and tub — the problem is likely in the main sewer line that they all connect to. A partial blockage in the lateral restricts flow from every fixture in the house.

2. Gurgling Sounds from Drains or Toilets

Gurgling sounds when you flush a toilet, run a sink, or drain a bathtub indicate air is being displaced in the drain system. This happens when a blockage in the sewer line forces air through water traps in other fixtures. If toilets gurgle when you run a washing machine or a sink gurgles when you flush, the sewer line deserves inspection.

3. Sewage Odors Inside or Outside

Sewer gas has a distinct rotten-egg smell that you should never detect inside your home or in your yard. If you smell it near drains, around cleanout access points, or in your yard above the sewer lateral path, it may indicate a cracked pipe, a failed joint, or a dry trap. Persistent outdoor odors along the path of your sewer line suggest the pipe has broken underground and waste is seeping into the surrounding soil.

4. Sewage Backups

Any sewage backup — even a small one — is a clear sign of a sewer line problem. If waste and water come up through a floor drain, shower drain, or toilet when you use other fixtures, the main sewer line cannot carry waste away fast enough. Causes include root intrusion, pipe collapse, heavy grease buildup, or an obstruction in the line.

5. Wet or Sunken Spots in the Yard

Unexplained wet or soggy areas in your yard, particularly along the path from your home to the street, can indicate a broken sewer line leaking wastewater into the soil. You may also notice unusually green, lush grass in one strip of the yard — the leaked wastewater acts as fertilizer. In some cases, the soil above a broken line settles or sinks, creating a visible depression.

6. Foundation Issues

A severe sewer line leak under or near your foundation can erode supporting soil over time, potentially contributing to foundation settlement or cracking. If you notice new cracks in your foundation, slab, or interior walls combined with any of the other signs on this list, a sewer line evaluation is warranted.

7. Pest Activity

Cracks and gaps in broken sewer lines provide entry points for insects and rodents. If you notice an increase in cockroaches, drain flies, or rodent activity that seems to originate from your plumbing, a compromised sewer line may be providing them access. A camera inspection can confirm whether the line has gaps that allow pest entry.

What to Do Next

If you recognize one or more of these signs, a sewer camera inspection is the most efficient next step. A waterproof camera inserted through a cleanout access gives a real-time video view of the pipe interior, showing the exact location and nature of any damage — roots, cracks, offsets, collapses, or buildup — without any digging.

Based on the inspection findings, a licensed plumber can recommend the most appropriate and cost-effective repair, which may range from targeted cleaning to trenchless relining to conventional replacement depending on the severity and extent of the damage.