How To Unclog a Sewer Drain in the Basement? (5 Step Guide)

Last Updated On November 30, 2021
how to unclog a sewer drain in the basement

The sewer drain is the unsung hero in any home, transferring the contents exiting your drains away from your home to the appropriate destination. 

A clogged sewer drain can mean disaster if not detected and treated with a sense of urgency. However, by the time you realize you have a problem, you probably have a stubborn clog on your hands. 

In this PlumbingNav guide, we will cover:

  • What you need to know about how to clear a main sewer line
  • Supplies you’ll need to clear a main sewer line
  • How to clear a main sewer drain line

What's In This Guide?

      What You Need To Know About How To Clear A Main Sewer Line Clog

      We’ve advanced immensely since the beginning stages of residential plumbing, but clogs and leaks in the sewage system happen.

      To start, it’s a good idea to understand how your home plumbing system works.

      All the unused water in your home makes its way through each drain, whether this is the sink, shower, or toilet drain. Every smaller drain leads to what is called the main drain line, which is a larger diameter pipe. This is located in your slab foundation 90% of the time.

      This main drain line moves waste water out of your home. Once the pipe exits your home, it’s typically called the sewer pipe. This is either connected to a septic system if you’re on private land, or the city sewer system. (80% of homes are on a city water system.)

      It continues along this journey until all waste finally reaches the local treatment plant. Of course, the setup varies slightly from municipality to municipality. 

      People may refer to the main drain and the sewer line as the same thing. For purposes of this article, we will treat it as such as we help you learn how to unclog it. 

      How long do sewer lines last? 

      Sewer lines often last 50 to 100 years. Many older ones were made of cast iron, and these can and will corrode over time. Cast iron sewer pipes’ life expectancy is about the same, however, if caustic chemicals are used this can speed corrosion.

      What causes sewer line clogs?

      As items flow down your drain, they can accumulate in the sewer pipe. 

      The main culprits include grease and fat, which makes it especially important for every homeowner to do their part to avoid creating a grease clog by not pouring grease and fat down the drain.

      Tree roots may also create a blockage.

      Other things that can create sewage backup include:

      • Paper products
      • Hair 
      • Food waste
      • Foreign objects

      How do I know if I have a sewer line drain clog?

      Early detection can save you a lot of money and hassle, so it’s important to know what to look for.

      A sewer line clog can result in leaks in your yard or throughout your house if the pressure becomes too much and causes a broken plumbing fixture. 

      Here are some of the signs of sewer system failure:

      • Gurgling toilet
      • Foul odor
      • Sewage backup
      • A clogged drain in sinks and showers
      • Discolored water
      • Basement flooding

      Sewer backup, in particular, can be a mess to deal with, and a flooded basement comes with expensive repairs.

      did you know how to unclog a sewer drain in the basement

      Supplies You’ll Need To Clear A Main Sewer Line Clog

      Drain Cleaner 

      A drain cleaner can eat through the material, creating the clog. 

      You have three main options when it comes to drain cleaners:

      • Homemade drain cleaner made out of vinegar and baking soda
      • Chemical drain cleaner that uses sulfuric acid or other chemicals
      • Natural drain cleaner that uses natural enzymes and bacteria


      An auger reaches deep into your plumbing system to break the clog up at the source with a pointed end, making it an immediate and effective solution. 

      Most augers reach 25 feet. 

      Portable Power Washer 

      A power washer provides high-pressure bursts of water, using the combination of both the power and the water to get things clean. 

      Protective Gear

      Working on a sewer drain can get messy. That’s why it’s important to have adequate protective gear. 

      Look for old clothes that cover your arms and legs as well as gloves and goggles. Sewage water contains bacteria and other materials that can be harmful. You want to ensure that you don’t come into direct contact with it. 

      How To Clear A Main Sewer Line Clog (5 Steps)

       In most cases, the best way to access your main sewer line is through a basement floor drain or cleanout. 

      Step 1: Turn Off Water

      Start by turning off the water to your home. In most cases, you’ll find the water main near the water meter. 

      Turning off the water prevents additional water damage in the case of any leaks or a complete clog. It also allows you to reach the clog instead of trying to work through standing water. 

      Step 2: Drain Cleaner

      Once you allow the water to clear out of the main drain, apply the drain cleaner of your choice. 

      A chemical drain cleaner may work on tough clogs quickly, but it can potentially damage your pipes. 

      On the other hand, an enzymatic drain cleaner may require you to wait overnight, and even the best natural drain cleaners aren’t as effective as chemical drain cleaners. That’s not to say that natural drain cleaners don’t work. However, they work better as part of plumbing maintenance as opposed to handling tough clogs. 

      Step 3: Drain Snake 

      If you have access to an auger, enter it into the nearest drain, which is usually located on your basement floor. After you place the auger into the basement drain, guide it until it reaches the sewer clog. 

      Once you have reached the clog, turn the power on to break up the clog. 

      If the clog isn’t near enough for the auger to reach it, you may need to take further action. 

      Step 4: Clear the Cleanout

      A sewer cleanout provides access to the main sewer line for just this very reason.  

      The clearout is usually located outside somewhere near the house or the sewer line. Once you locate the cleanout, you will open it using a wrench. 

      Next, you will use the power washer to remove the clog. 

      To use the power washer, apply the sewer jetter attachment. After you slide the nozzle about a foot deep, you will pull the trigger to activate the power washer. Continue to pull down on the trigger in a pulsating pattern until you hear the drain open. 

      Always clean the sewer jetter attachment thoroughly after you finish using it. 

      Step 5: Call Plumber

      If the clog still doesn’t clear up, it’s time to enlist professional plumbing repair services. 

      On average, having a plumber clear out your sewer line will cost $475. However, you should look up information in your area about whether the responsibility for the repair falls on you as the homeowner or the city.

      Final Thoughts On How To Unclog A Sewer Drain In The Basement 

      If you notice a clogged basement drain, you probably have a sewer clog that could lead to unpleasant drain backup. Take action before the problem gets out of control using our guide on how to unclog a sewer drain in the basement. 

      Once you create a drain opening, take the proper precautions to prevent the problem from happening again by not pouring grease down the drain and using natural drain cleaners monthly. 

      FAQS For How To Clear A Main Sewer Line Clog

      Can I unclog my own sewer line?

      Yes! You can unclog your sewer line yourself using a drain cleaner, an auger, or a power washer 

      How do you unclog a main sewer line without a snake?

      To unclog a main sewer line without a snake, you should try a drain cleaner or a power washer.  

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

      On average, it costs $475 for professional sewer line repair. 

      What can I do if my main sewer line is clogged?

      If you have a clogged sewer line, follow these steps:

      • Step One: Turn off your water
      • Step Two; Use a drain cleaner
      • Step Three: Use a drain snake
      • Step Four: Clear the cleanout
      • Step Five: Call a plumber

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