How to tell if the main sewer line is clogged?

Author: Lemuel Bernhard  |  Last update: Friday, September 5, 2025

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.

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

4 Signs Your Main Sewer Line Is Clogged
  1. Sign #1: Multiple drains are backing-up.
  2. Sign #2: Drainage appears in sewer clean out.
  3. Sign #3: Sewage in floor drain.
  4. Sign #4: Water backs up in shower when toilet flushes.

How do I unblock my main sewer line?

Your step-by-step guide: How to clear a main sewer line clog
  1. Loosen the cap on the drain pipe. ...
  2. Allow any sewer buildup to come out of the drain. ...
  3. Gently feed the auger cable into the main line drain. ...
  4. Run the auger until the clog is broken up. ...
  5. Hose out leftover debris. ...
  6. Pull the auger cable back out of the main line drain.

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 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.

Signs of a Clogged Sewer Line and What to Do About It

How to tell if your sewer is backed up?

Here are some signs to look out for.
  1. Smells and Odors. The first and most common sign that there is a sewage backup somewhere in your house or business is the smell. ...
  2. Sinks and Toilets Overflowing. ...
  3. Gurgling Noises. ...
  4. Slow Drains. ...
  5. Puddles and Pooling Water. ...
  6. Sinkhole Developing. ...
  7. Mold and Mildew Growth. ...
  8. Insect Activity.

How to tell if an outside drain is blocked?

This blog will point out the key signs to look out for before discussing the steps to take when you think your drainage system is clogged.
  1. Slow Drainage. ...
  2. Unpleasant Smells and Odours. ...
  3. Gurgling Sounds Coming from Drains and Plug Holes. ...
  4. Raised Water Levels.

Is a clogged sewer line covered by insurance?

Homeowners insurance may cover sewer line damage if it stems from something already included in your policy, like a fire or windstorm. Sewer line damage that is the result of wear and tear is excluded from home insurance coverage.

Will Drano unclog a main sewer line?

With a clogged basement drain, pouring Drano or similar products down your sewer drain can actually damage your pipes or the glue holding them together, causing more sewer system problems in the future.

Who is responsible for blocked sewers?

Repairs to sewers

Sewers and lateral drains connected to the public network used to be the responsibility of the property owner. However, most are now maintained by local water companies. If you have any problems with your sewer or lateral drain, for example if it's blocked, contact your local water company.

Can a plunger unclog a main sewer line?

A plunger works to unclog the main sewer line because it creates an airtight seal with the drain. In the process, it helps force the stubborn clog out of the plumbing system drains.

How much does hydro jetting cost?

Hydro jetting costs $475 on average but range from $350 to $600. A plumber can give you a quote and get rid of your sewer clog. Having to keep your plumber on speed dial is no fun for any homeowner. If chronic sewer clogs are giving you issues, it might be time to call in the big guns.

How do I stop my main sewer line from clogging?

10 Tips to Prevent Clogging Your Sewer Line
  1. Install a Sewer Line Root Barrier. ...
  2. Use Drain Screens in Drains. ...
  3. Don't Flush Clumping Cat Litter. ...
  4. Keep Garbage Disposal Blades Sharp. ...
  5. Check/Repair Pipe Connections, Venting, and Seals. ...
  6. Never Pour Grease or Cooking Oil Down the Drain. ...
  7. Avoid Flushing Feminine Products Down the Drain.

What is the easiest way to clear a blockage in the sewer line?

Start by removing any visible and solid obstructions from the drain, like hair or food particles. Pour 1 cup of baking soda down the drain. Slowly pour the 2 cups of white vinegar down the drain over the baking soda. The mixture will create a fizzing reaction, which can help break down the gunk in the drain.

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

Read on to learn the signs of a frozen sewer pipe so that you can catch the problem before it gets worse.
  1. No Running Water. ...
  2. Visibly Frosty Pipe. ...
  3. Strange Sounds. ...
  4. Sewage Smells. ...
  5. Leaks.

How do I know if my sewer needs pumped?

Here are some signs that indicate it is time to pump your septic tank.
  1. Overdue Pumping.  ...
  2. Slow Drains. ...
  3. Standing Water. ...
  4. Overgrown Lawn Grass. ...
  5. Bad Odors. ...
  6. Gurgling Pipes. ...
  7. Sewage Backup.

How do I know if my main line is clogged?

Strange Smells and Noises

Foul smells emanating from your sink, bathtub or floor drain indicate a main sewer line blockage. The clog leaves nowhere else for the waste causing the smell to go, leaving a lingering odor. In addition to strange smells, you might also notice a gurgling noise coming from your drains.

How much does it cost to unclog a sewer line?

Snaking a main line—also known as rodding or augering—costs between $100 and $250, but it can leave residue or smaller debris. Hydro jetting uses a high-pressure hose for major clogs and clears out the pipe more extensively. This service runs a bit higher at $350 to $600.

How do I unclog my main sewer without an auger?

Using equal parts baking soda and vinegar, mix ⅓ cup of each together and pour down your drain. The chemical reaction may help loosen any blockages. Using hot water can help liquefy solidified grease and fats.

Does homeowners insurance cover sewer back ups?

While homeowners insurance protects you against some forms of unexpected water damage, water back-ups and sump pump overflows are usually not covered. You may purchase optional water back-up coverage that may pay for damages in the case of sewage back-up or a malfunctioning sump pump.

How often should a sewer line be cleaned?

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 main water line replacement?

If these are damaged or break, the homeowner might be responsible for the repair. A standard homeowners policy does not cover the service lines running into the home—unless you've added service line coverage.

How do I know if my underground drain is clogged?

If you notice water gushing back out from the drain pipe or leaking out from the seams on the adapter, that is a sign that there are clogs in your underground drain.

How do I unblock my outside sewer drain?

Boil a kettle full of water and, wearing long sleeve gloves, goggles and a mask, pour it down the outside drain being careful not to cause any to splash back onto your skin. If hot water doesn't work, you can try using caustic soda, also known as sodium hydroxide.

How do I know if my sewer is blocked?

Smelly, noisy or slowly moving drains

Again, if there's an issue with the main sewage line, all the drains will be affected. So if all the drains in your house smell bad, produce gurgling noises, or they are draining slowly - the main sewage line could be blocked.

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