What is your main sewer line?

Author: Verner Hegmann  |  Last update: Tuesday, June 9, 2026

What is the Main Sewer Line? The main sewer line is exactly what you think it is. It's the plumbing line that channels all of the waste from toilets, tubs, and sinks out of your home, toward the main sewer under the street in front of your home.

How do I locate my main sewer line?

It can typically be found in the basement, crawl space or garage. You will want to search for a pipe that is approximately four inches in diameter with a screw cap on the top that has a notch or square knob at the top. Note that some homes have an indoor sewer cleanout point, while others may be located outdoors.

What is considered the main sewer line?

What is a Main Line? To put it simply, your main line is your sewer line. It's a line located underground that carries all wastewater from your home to a municipal connection or septic tank, not just toilet water.

Does homeowners insurance cover main sewer line replacement?

Does homeowners insurance cover your sewer line if it's damaged? Damage to your sewer line may be covered by your policy if it is caused by perils such as hail or windstorms, explosions, lightning or fire, damages caused by vehicles, vandalism or falling objects.

How do I know if my main sewer line is clogged?

When the sewer line that carries waste away from the house is blocked, you'll notice the four signs that follow.
  1. All Your Drains Reek. ...
  2. Your Drains Are Blocked or Slow-Moving. ...
  3. You Hear Loud Gurgling Sounds Coming From Your Pipes Throughout Your Home. ...
  4. You Have an Unnaturally Lush Landscape or a Smelly, Sunken Lawn.

Top 4 Things You Need to Know About Your Main Sewer Line

How much does it cost to unclog a main sewer line?

You will likely pay around $350 to $650 to have a plumber unclog a main sewer line unless you have complications like serious damage to the line.

How do I know if my sewer line needs to be replaced?

7 Warning Signs Your Sewer Line Needs to Be Replaced
  1. There's a Spike in Your Water Bill. ...
  2. You Hear Gurgling Coming from the Pipes. ...
  3. The Water Is Slowly Draining. ...
  4. Your Yard is Soggy. ...
  5. The Smell of Sewage Lingers. ...
  6. Pests Are Attracted to Your Yard. ...
  7. The Toilet Bowl Water Level Is Up and Down.

How much to replace a main sewer line?

Sewer line replacement costs stem from labor, permits, materials, excavation, and landscaping restoration, potentially running from $4,000 to $25,000. Trenchless sewer replacement methods can save long-term costs by minimizing disruption and avoiding extensive excavation, despite higher initial charges.

How many years does a sewer line last?

Generally speaking, you're going to find that most main sewer lines will only last somewhere between 50 and 100 years before you need to do a main sewer line replacement. You could very well have a broken sewer line on your hands right now and not even realize it.

Are local governments responsible for paying for sewer line repairs?

Sewer laterals are the underground pipes that connect your home wastewater to the main sewer line in the street. Homeowners are responsible for their sewer laterals, while problems with the public sewer main line are managed by the city or municipality.

How to clear a main sewer line clog yourself?

Your step-by-step guide: How to clear a main sewer line clog
  1. Step 1: Loosen the cap on the drain pipe. ...
  2. Step 2: Open the cap and let the buildup drain out. ...
  3. Step 3: Feed the auger cable into the drain pipe. ...
  4. Step 4: Run the auger until the clog is clear—and beyond. ...
  5. Step 5: Hose down the pipe and auger cable.

How deep is a main sewer line buried?

For instance, residential sewer line depth ranges from 18 to 30 inches. However, city sewer line depths are different. Your city's sewer lines must always be deeper than the deepest residential pipe to allow waste to flow downhill. As such, these lines can go as deep as needed.

What is the difference between a drain line and a main line?

your drain line. The main sewer line is outside the home, while drain lines are inside your house. When these systems need maintenance or repairs, the type of plumber you should call will depend on whether the problem is in a drain line inside your home or the main sewer line outside your home.

What does the main sewer line look like?

You may spot a 3 to 4-inch diameter pipe peeking out of the slab floor of the basement. The sewer drain pipe could be made of plastic or cast iron; it might be copper or brass in rare cases. The stub-out will have a screw-in plug coupled with a square-head lug on it, representing your access to the main drain.

Does every house have a sewer line?

At this point almost all homes have a sewer cleanout. The only houses that don't are older homes in which a cleanout wasn't installed originally. But even if you're in an older home that was built without a sewer cleanout, it's likely one was needed at some point and was installed.

How do I test my main sewer line?

Test Balls for Drainage Lines

To start the process, make sure your main line sewer cleanout is clear of debris and liquid. Next, insert the test ball and inflate it so that it blocks the main line. Fill the sewer system with water and observe the water level for 15-20 minutes.

Can you replace a main sewer line yourself?

As we mentioned above, it's certainly possible for a homeowner to perform sewer line replacement or sewer line repair. However, it's definitely not an easy job. When you replace the sewer line yourself you run the risk of causing even more damage.

Why is sewer line replacement so expensive?

One of the primary reasons for the high cost of sewer line replacement is the labor-intensive nature of the job. Replacing a sewer line involves excavating the ground to access the damaged pipe, removing the old pipe, and installing a new one.

How often should you clean your main sewer line?

Expert Recommendations for Sewer Line Cleaning

We recommend homeowners schedule sewer line cleaning every 18 to 24 months to prevent buildup and clogs. Regular cleanings help avoid costly repairs and extend the life of your plumbing system.

Does homeowners insurance cover sewer lines?

In most cases, home insurance will cover sewer line damage from specific events. This includes extreme weather (excluding earthquakes and floods), vandalism, fire, and damage from vehicles or falling objects.

How do you know if your main sewer line is broken?

The Top 10 Most Common Signs of Broken Sewer Lines
  • Sewer Smell. Usually, one of the first signs of a sewer line is a bad odor. ...
  • Gurgling Toilet. ...
  • Pests in Your Home. ...
  • Slow Drains. ...
  • Sewage Backup in Your Toilet or Tub. ...
  • Mold or Mildew On Your Ceilings or Walls. ...
  • Cracks in Your Walls. ...
  • Unusually Green Patches on Your Lawn.

What is the difference between a sewer line and a sewer main?

Main drains are located in the walls and floors of your home, while sewer line drains are located outside underground. Each drain pipe in your home is connected to a different household fixture on one end, including toilets, sinks and bathtubs, and the other end is connected to the main sewer line.

What is the cheapest way to replace a sewer line?

Trenchless sewer repairs, such as pipe lining or pipe bursting, are typically 30-40% less expensive than traditional excavation and less invasive. Traditional excavation, which involves digging a trench to access the damaged pipe, is usually more expensive and can cause significant damage to your yard.

How long does it take to replace a main sewer line?

Typically, to replace a sewer line it can take anywhere from 1 to 2 days, to 3 to 5 days. In some rare cases, it may even be as quick as one day. Generally, the estimated time frame will depend on the layout of your property, your home's piping system, and the depth required to excavate.

Do plumbers check sewer lines?

Professional plumbers can use various camera styles to inspect the sewer line, such as: Remote-controlled crawler cameras. Pole or fixed zoom cameras. Push rod cameras.

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