7 Signs Your Sewer Line Is Failing (Sonoma County Guide)

Your home’s sewer line is the most important pipe you never see. When it fails, the consequences range from inconvenient (multiple slow drains) to catastrophic (sewage backing up into your home). The good news: sewer lines almost always give warning signs before they fail completely. Here are the seven most common ones.

1. Multiple Drains Backing Up Simultaneously

If your toilet gurgles when you run the bathroom sink, or water backs up into the tub when you flush, that’s a main sewer line problem — not individual fixture clogs. When multiple fixtures fail together, the blockage is downstream of all of them, in the main lateral.

2. Sewage Odor Inside or Outside Your Home

A properly functioning sewer system is completely sealed. Any sewage odor inside (from drains, vents, or floor areas) or a persistent septic smell in your yard indicates a crack, break, or disconnected joint in the line.

3. Soggy, Lush, or Unusually Green Patches in the Yard

Sewage is an excellent fertilizer. A lush, green patch of grass in an otherwise uniform lawn — especially if the ground is soft or wet — often indicates a leaking sewer line below. This is more common in older Sonoma County homes with clay or cast iron sewer pipes.

4. Slow Drains Throughout the Entire House

A single slow drain is usually a local clog. When every drain in the house runs slow simultaneously, the obstruction is in the main sewer line. Common causes in Sonoma County include tree root intrusion (very common with mature oaks and redwoods) and collapsed or offset pipe sections.

5. Gurgling Toilets

When you flush and hear gurgling from the toilet (or from other nearby fixtures), air is escaping from a partial blockage in the main line. This is the sewer line trying to vent through your toilet because the normal venting path is blocked.

6. Foundation Cracks or Unexplained Settling

In severe cases, a long-term sewer leak under or near a foundation can erode the soil beneath it, causing settlement and cracking. If you’re seeing new cracks in your foundation or floors and any of the other signs above, have your sewer line inspected immediately.

7. Your Home Was Built Before 1980

This one isn’t a symptom — it’s a risk factor. Homes built before 1980 in Sonoma County commonly have cast iron, clay tile, or Orangeburg (fiber) sewer pipes that are at or past their useful life. We recommend proactive camera inspections for all pre-1980 homes, even without symptoms, every 3–5 years.

What a Camera Inspection Shows

A sewer camera inspection runs a waterproof camera through the main line and records what’s inside. We can see root intrusion, cracks, offset joints, grease buildup, collapsed sections, and bellied pipe. It’s the only way to know what you’re dealing with before committing to repair costs.

Pre-purchase sewer inspections are one of the most valuable inspections a homebuyer can get. Many Sonoma County real estate transactions now include sewer camera inspections as a standard contingency.

See also: Sewer Line Repair & Replacement | Drain Cleaning