Signs You Might Have a Broken Sewer Line Under Your Yard

Coastal Rooter helps San Diego homeowners spot hidden sewer line problems before they cause major yard or foundation damage. Learn the warning signs of a broken sewer line underground.

A broken sewer line under your yard can go unnoticed for weeks—until the signs become impossible to ignore. The sooner you catch the symptoms, the less damage you’ll face from sewage leaks, erosion, or even foundation trouble.

Here are the most common signs of a broken sewer line under your yard and what to do if you notice them.

Unusually soggy patches or sinkholes

If your lawn has an area that’s always damp—even during dry weather—it could be caused by wastewater leaking from an underground pipe. In severe cases, the soil may erode enough to form soft spots or even small sinkholes.

This is especially concerning near your home’s foundation, driveway, or walkways, where water can destabilize the ground and lead to cracking or shifting.

Foul odors outside

Smelling something bad in your yard? Sewer gas smells like rotten eggs or sulfur. If it’s noticeable outside—especially near sewer cleanouts or flower beds—it may mean sewage is escaping underground.

Even small cracks in a sewer line can release gases that make your property smell unpleasant. A healthy sewer system should be airtight and odor-free.

Sudden growth of lush, green patches

Wastewater is rich in nutrients. When it leaks into your soil, it can cause grass or plants to grow more quickly than normal. If you notice a particularly vibrant patch of grass, or bushes that are thriving while others struggle, you might have a leak below.

This is especially suspicious if the area lines up with your main sewer route between the house and the street.

Slow or backed-up drains inside the home

A damaged sewer line outside can cause backups inside. Toilets may flush slowly, tubs may drain poorly, or you might hear gurgling from sinks and drains. If multiple fixtures in your home are affected, the problem is likely in the main sewer line—not just a clogged pipe.

Don’t ignore these signs. Blockages or breaks outside the home affect the entire system and often require professional inspection and repair. Check out our drain cleaning services.

Rodent or insect activity

Cracks in underground pipes give pests like rats and cockroaches easy access to your plumbing system. If you suddenly notice more insects or rodents around your property, a broken sewer line could be to blame.

These pests are attracted to the moisture and waste—and once they’re in, they’re hard to get rid of.

Foundation or slab movement

In extreme cases, sewer line breaks can erode soil beneath your home’s foundation, causing cracking or uneven settling. This usually happens over time but can be accelerated by large leaks or old, collapsing pipes.

Look for:

• New cracks in walls or floors
• Doors that don’t close properly
• Uneven flooring

These structural issues are serious and require immediate attention. Schedule a sewer inspection to check for damage.

What causes a broken sewer line?

Several factors can damage underground sewer pipes:

• Tree root intrusion: Roots seek out moisture and can invade joints or cracks
• Old pipes: Clay and cast iron pipes can corrode or collapse over time
• Shifting soil: Earth movement from rain, drought, or construction can displace pipes
• Poor installation: Misaligned or shallow pipes are more prone to breakage

San Diego’s mix of older homes and tree-lined streets means root damage and aging materials are common causes.

How plumbers detect underground sewer problems

Coastal Rooter uses specialized tools to find hidden sewer line issues without digging up your yard unnecessarily. These include:

• Sewer camera inspection: A small camera is fed through the pipes to visually identify cracks, blockages, or misalignments.
• Smoke testing: Non-toxic smoke is blown through the system to detect leaks or bad connections.
• Pipe locators: Electronic locators help map out exactly where the line is and where damage exists.

Learn more about our trenchless sewer line repair process.

San Diego homeowners should know

San Diego’s mild climate can mask early signs of sewer problems because soil rarely freezes or cracks naturally. But tree roots, clay pipes, and historic neighborhoods increase the risk of underground damage.

Coastal Rooter specializes in finding and fixing these problems fast. Whether you live in North Park, La Mesa, or Chula Vista, their team:

• Responds quickly to sewer line concerns
• Offers trenchless repair to minimize yard damage
• Provides detailed inspection reports for insurance or real estate purposes

“We saw a soft patch in the yard and assumed it was irrigation. Coastal Rooter found a cracked sewer pipe and fixed it without digging up our whole lawn.” — San Diego homeowner

For more information on preventing water system issues, visit the EPA’s plumbing guide.

Don’t wait for a sewer disaster

If you notice signs of a broken sewer line, call 619-383-2210 to book an inspection. Coastal Rooter locates the problem fast and recommends the right solution—before the damage spreads.