Top Signs You Have a Clogged Main Sewer Line

Coastal Rooter helps San Diego homeowners identify and fix main sewer line clogs before they cause serious damage. Recognizing the signs early can protect your home and avoid costly backups.

A clogged main sewer line is one of the most serious plumbing problems a homeowner can face. Unlike a slow sink or toilet clog, a main line blockage affects the entire drainage system of your home. When it clogs, wastewater has nowhere to go—and that can lead to backups, flooding, and even health hazards.

Here are the top signs your main sewer line might be clogged, and what to do if you notice them.

Multiple Drains Are Backing Up at Once

If several drains in your home are slow or backing up at the same time, it’s a red flag. A single clogged drain usually means a localized issue. But when your sinks, tubs, and toilets all show signs of poor drainage, the problem is likely in the main sewer line.

Watch for signs like:

• Water backing up in the shower when you flush the toilet
• Gurgling sounds in drains
• Slow drains in multiple bathrooms

These symptoms point to a blockage further down in the plumbing system—often beyond the reach of household tools.

Strange Sounds Coming From Your Pipes

Unusual noises like bubbling, gurgling, or groaning from your toilets or drains can mean trapped air is being forced through water due to a clog. This often happens when waste can’t flow freely through the sewer line.

Gurgling is especially noticeable after flushing a toilet or draining a bathtub. If you hear it often, don’t ignore it—it may signal an issue that’s getting worse.

Water or Sewage Coming Up From Floor Drains

One of the most obvious signs of a clogged main line is water backing up through the lowest drains in your home—typically basement floor drains or first-floor tubs.

If you notice water, debris, or even sewage coming up from a floor drain, act fast. This is not only unpleasant but also a potential health hazard.

Frequent Toilet Clogs or Poor Flush Performance

If your toilet clogs more often than usual or takes longer to flush, it may be more than just a paper issue. A main line clog slows the overall drainage, causing toilets to struggle even when they aren’t directly blocked.

You may also notice that plunging or snaking the toilet doesn’t fix the problem for long. That’s a strong sign the issue lies deeper.

Wet Spots or Soggy Patches In Your Yard

The main sewer line typically runs underground from your house to the street. If that pipe breaks or leaks due to tree roots or blockages, you may see unexplained soggy areas or patches of grass growing faster than the rest.

This is especially important to check in San Diego homes with older clay or cast iron sewer lines, which are more vulnerable to root intrusion and corrosion.

Strong Sewage Smells Indoors or Outside

A healthy sewer system is sealed and odor-free. If you start noticing foul smells inside your home—especially near drains or in the basement—it could indicate a backup is brewing.

Outdoor sewer smells near your foundation or in the yard are also cause for concern. Both point to a potential breach or blockage in the main line.

“We had strange smells and slow drains for weeks. Coastal Rooter found a massive clog in our main line and cleared it out the same day. Life-saver!” — San Diego homeowner

What Causes a Clogged Main Sewer Line?

Main line clogs usually result from a combination of:

• Tree root invasion (especially common in older neighborhoods)
• Flushing wipes, hygiene products, or grease
• Heavy buildup of sludge, soap, or debris
• Collapsed or cracked pipes

Older homes in San Diego are particularly vulnerable to sewer problems due to aging pipe materials and nearby landscaping.

Professional Solutions For Sewer Line Clogs

Clogged main lines require professional equipment. At Coastal Rooter, we use:

• Sewer camera inspections to locate the blockage
• Hydro jetting to clear tough clogs with high-pressure water
• Trenchless sewer repair when pipes need replacement

These services are fast, effective, and protect your property from major damage. Explore our sewer line services.

How to Prevent Main Line Clogs

You can’t always avoid plumbing issues, but a few smart habits reduce the risk:

• Don’t flush wipes—even “flushable” ones
• Avoid pouring grease down the drain
• Use drain screens to catch hair and debris
• Schedule annual plumbing inspections to spot early issues

If your home has had previous main line clogs, ask about our sewer camera inspections to track ongoing problems.

Need expert help? The EPA’s plumbing guide offers additional tips on home water systems.

Get Support For Main Line Clogs Fast

When you need help with a clogged sewer line, call 619-383-2210 to schedule service. Coastal Rooter finds and clears main line blockages quickly—before they cause bigger problems.