7 Signs of a Broken Sewer Line Under Your Yard

If several drains in your home are slowing down at once, you smell sewage in the yard, or one patch of lawn is suddenly greener than the rest, those are classic warning signs of a broken sewer line buried under your property. Your sewer line (also called the sewer lateral) is the single underground pipe that carries everything from your home's drains out to the city main — and when it cracks, sags, or fills with roots, the whole house feels it. I'm Jesse Delgado, owner of Flow Pro Plumbing here in Brentwood, and this is the guide I wish every East Bay homeowner read before a small sewer problem turned into a torn-up yard.

What is a sewer line, and what does "broken" actually mean?

Your sewer line is the main drainpipe that connects every toilet, sink, shower, and floor drain in your home to the public sewer. "Broken" doesn't always mean snapped in half — in the field we use it for any failure that stops wastewater from flowing freely: a crack, a collapsed section, a sag or "belly" that holds water, an offset joint where two pipe sections have shifted apart, or a pipe so packed with tree roots that nothing can get past. Because the line is buried three to six feet (or deeper) under your yard, you almost never see the damage. You see the symptoms inside the house first.

What are the 7 signs of a broken sewer line under your yard?

The fastest way to catch a failing sewer line is to watch for these seven signs — and the more of them you notice together, the more likely the problem is the main line, not a single fixture:

1. Multiple drains are slow or backing up at the same time. One slow sink is usually a local clog. When your toilet, tub, and kitchen sink all drain poorly at once, the blockage is downstream in the shared sewer line. If it really is just one fixture, start with our guide on why drains clog and the warning signs of a bigger problem.
2. A sewage smell in your yard or home. A healthy sewer system is sealed and vented. If you catch a rotten-egg or raw-sewage odor near a drain or out in the yard, sewer gas is escaping through a crack or open joint.
3. Soggy, sunken, or unusually lush patches in the lawn. Leaking wastewater acts like fertilizer. A bright-green stripe, a spongy area, or a low spot that never dries out often traces the exact path of a leaking sewer line.
4. New foundation cracks, settling, or sinkholes. A chronic underground leak washes away the soil that supports your slab and hardscape. Fresh cracks in the foundation, driveway, or patio — or a dip forming in the yard — can point straight back to the sewer.
5. Rodents or insects showing up indoors. Rats and sewer flies live in sewer lines. A break gives them a direct path into your walls and home, so a sudden pest problem can be a plumbing problem in disguise.
6. Gurgling toilets and drains. If your toilet bubbles or you hear glug-glug from a drain when you run water elsewhere, air is being trapped by a partial blockage in the main line.
7. Backups that keep coming back. If sewage rises into your lowest drain — a downstairs tub, shower, or floor drain — or you've had the same line snaked more than once in a year, the underlying pipe is compromised, not just clogged.

What causes a sewer line to break in East Contra Costa homes?

Most sewer failures we dig into around here come down to three things: roots, age, and ground movement. Thirsty tree and shrub roots find the bit of moisture at a pipe joint and grow inside until they choke the line — the number-one cause we see. Age is the second: many older homes in Concord, Antioch, and Pittsburg were built with clay or Orangeburg (tar-paper) sewer pipe that turns brittle, cracks, and crushes over the decades. The third is ground shift — our expansive East Bay clay soils swell when wet and shrink when dry, and that constant movement (plus the occasional seismic nudge) pulls pipe joints apart and creates bellies. Grease, scale, and "flushable" wipes then snag on every rough edge and finish the job.

Why is a camera inspection the only way to know for sure?

Because the pipe is buried, the only honest way to diagnose a sewer line is to look inside it. A sewer video inspection sends a waterproof HD camera down the line so we — and you, watching the monitor — can see exactly what's wrong, how bad it is, and precisely where it is. No guessing, and no digging up the yard just to "find out." That single step tells us whether you need a simple cleaning, a hydro-jetting to cut out roots and scale, or an actual repair. If you want to understand the difference between clearing a line and replacing it, our companion guide on hydro-jetting vs. snaking breaks it down.

What should you do if you think your sewer line is broken?

Stop putting water down the drains and get the line inspected before the next backup. If raw sewage is coming up inside the house, treat it as an emergency — that's exactly what our 24/7 emergency plumbing line is for. Once a camera confirms the damage, your next decision is how to fix it, and you usually have options: in many cases we can repair the line with minimal digging. Read trenchless vs. traditional sewer repair to compare the methods, pros, cons, and what drives the cost, then see our full sewer repair service for what we actually do on site.

Why East Bay homeowners trust Flow Pro for sewer problems

Flow Pro Plumbing is a family-owned, husband-and-wife company based in Brentwood, and our team is CSLB C-36 licensed and insured. We've earned a 4.9-star rating across 900+ Google reviews, were voted Best of Oakley in 2021, and earned a Best of Houzz award in 2018 — and we put every technician through weekly training, so the person reading your camera footage actually knows what they're looking at. You can read those customer reviews yourself and see every community we cover on our service areas page. If you'd rather get ahead of sewer trouble entirely, a maintenance plan keeps your drains and main line on a regular check-up schedule.

Frequently Asked Questions

How do I know if it's a clog or a broken sewer line?

A single slow fixture is almost always a local clog. A broken or failing sewer line usually shows up as several fixtures backing up at once, gurgling, recurring backups, and outdoor clues like odor or a soggy lawn. The only way to be certain is a camera inspection of the line itself.

Will I have to dig up my whole yard to fix it?

Not necessarily. Many sewer repairs in our area can be done trenchless — lining or replacing the pipe through small access points instead of an open trench. Whether that's an option depends on the condition and shape of your existing line, which the camera inspection tells us. See our trenchless vs. traditional comparison for the details.

Is a sewage backup an emergency?

Yes. Sewage rising into your home is a health hazard and can cause fast, expensive damage. Stop using water and call our 24/7 emergency team right away.

Do I need a sewer inspection before buying or selling a home in the East Bay?

It's one of the smartest inspections you can buy, and some East Bay communities have point-of-sale sewer lateral rules that require a compliance certificate. We cover what that means in our guide to sewer lateral compliance and resale.

What does a sewer camera inspection cost?

We'll give you the price up front before we run the camera, then show you the footage and explain what it means in plain language.

Not sure where to start? Contact Flow Pro Plumbing and we'll get a camera on your line. You can also explore the rest of our Learning Center or look up any term in the plumbing glossary.