How to Use a Main Line Cleanout to Clear a Major Sewer Clog
About This Project
This guide provides verbose, step-by-step instructions for clearing a major sewer line clog by accessing the main line cleanout port and using a heavy-duty electric drain auger. It covers essential safety precautions, locating the cleanout, correctly operating the auger to break through the obstruction, and verifying that the drain is clear before cleanup.
Best for advanced DIYers and professionals with basic plumbing knowledge. Requires Safety Glasses and Carhartt Men's 08M/W Blk PU Coated Leather/Brn Leather Shaft Waterproof Insulated Composite Safety Toe 10 in. Work Boot CMC1259-08M/W and FIRM GRIP Large Cowhide Leather Work Gloves 63857-06.
Tools & Materials
5 Gal. White Bucket with Rope Handle 2451
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Safety Glasses
Carhartt Men's 08M/W Blk PU Coated Leather/Brn Leather Shaft Waterproof Insulated Composite Safety Toe 10 in. Work Boot CMC1259-08M/W
5 Gal. White Bucket with Rope Handle 2451
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Walls Republic Textile Print Mustard Plain Non-Woven Paste the wall Textured Wallpaper 57 sq. ft. R8206
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PROTARP 12 ft. x 12 ft. White 22 Mil Heavy Duty Polyethylene Tarp, Waterproof, UV Resistant, Rip and Tear Proof PT-204-12X12
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Safety Glasses
Keeps eyes safe from potential hazards.
Carhartt Men's 08M/W Blk PU Coated Leather/Brn Leather Shaft Waterproof Insulated Composite Safety Toe 10 in. Work Boot CMC1259-08M/W
Carhartt Footwear brings new life to an old concept; quality work footwear. We build footwear using the highest standards of design, componentry and construction to insure that the Carhartt product you
Steps
Prepare Work Area and Wear PPE
15 minsBefore starting any work, prioritize your safety and prepare the work area to contain the mess. Put on your full personal protective equipment (PPE), including heavy-duty waterproof gloves and safety glasses. It is highly recommended to wear old clothes and work boots. Lay down thick plastic sheeting or tarps on the floor around the main line cleanout to protect the surface and make cleanup easier. Place a large, empty bucket directly underneath the cleanout plug to catch any initial backflow of sewage.
Locate the Main Cleanout
10 minsLocate the main line cleanout in your basement. It is typically a large-diameter pipe (3 or 4 inches) made of cast iron or PVC that runs horizontally near the floor and exits through the foundation wall. You are looking for a 'Y' shaped fitting with a threaded plug or cap at the top of the 'Y' branch. The plug often has a square, raised nut on its top for a wrench. Use a flashlight if the area is poorly lit to confirm you have identified the correct access point.
Open the Cleanout Plug
15 minsPosition your body to the side of the cleanout plug, not directly in front of it. Fit a large pipe wrench or an adjustable wrench onto the square nut of the plug. Exert steady pressure to turn the plug counter-clockwise. It may be very tight due to age and corrosion. Be prepared for wastewater to begin seeping or flowing out as the threads loosen. Open it slowly, allowing the pressure to release gradually and the initial backup to drain into the bucket. Once the flow stops, you can fully remove the plug and set it aside.
Set Up and Insert the Auger
15 minsPosition your rented electric sewer auger a few feet from the cleanout opening, ensuring it is stable. Make sure the direction switch is in the 'Forward' or 'FWD' position. Put on a pair of thick leather work gloves over your waterproof gloves to protect your hands from the spinning cable. Carefully feed the end of the auger cable, which has a cutting head attached, into the cleanout pipe. Push it in by hand until you feel it stop or meet the first bend.
Operate the Auger to Clear the Clog
30 minsWith the cable inserted into the pipe, turn on the auger's motor. Use the foot pedal to control the cable's rotation. Firmly grip the cable with your gloved hands and slowly advance it further into the pipe. When you feel the cable stop advancing, you have reached the clog. Do not force it. Instead, allow the rotating cutting head to do its work. You may need to pull the cable back a foot or two and then advance it again several times. This back-and-forth motion helps the cutting head chew through the obstruction. Listen to the motor; a change in sound can indicate you have broken through. Continue to feed the cable another 5-10 feet past the blockage to ensure the line is fully clear.
Retrieve the Auger Cable
20 minsOnce you believe the clog is cleared, switch the auger's motor to the 'Reverse' or 'REV' setting. Activate the motor with the foot pedal and begin slowly retrieving the cable. Have a rag in one hand to wipe the cable clean as it comes out of the pipe, guiding the dirty water and debris back into the bucket or drain opening. This is a critical step to minimize the mess in your basement.
Test the Drain Line
10 minsBefore replacing the cleanout plug, you must verify the clog is gone. Ask a helper to flush a toilet on the ground floor (not the basement) a few times. Alternatively, you can run a large sink or bathtub faucet for several minutes. Watch the water flow inside the open cleanout pipe. The water should flow swiftly down the drain without any signs of backing up. If it backs up, you may need to repeat the augering process.
Close the Cleanout and Clean Up
30 minsOnce you've confirmed the line is clear, it's time to close up and clean. Use a rag to wipe the threads on both the cleanout plug and the pipe fitting. For a better seal, wrap the male threads of the plug with a few layers of Teflon tape in a clockwise direction, or apply a thin coat of pipe thread sealant. Insert the plug and hand-tighten it. Finish tightening it securely with the pipe wrench, but do not overtighten to the point of cracking the cast iron fitting. Carefully roll up the dirty tarps, dispose of heavily soiled rags, and use a disinfectant cleaner to sanitize the floor, tools, and any surfaces that were exposed to sewage.
Common Problems
Standard plungers fail to create a seal, making toilet clogs harder to clear.
Solution: For a toilet clog, a flange or accordion plunger is more effective than a standard cup plunger as it creates a better seal in the toilet bowl's drain opening.
Be aware that you can push a smaller clog into a larger one further down the line, creating a more severe blockage.
Solution: To avoid this issue: Be mindful of this warning and take appropriate precautions.
Clog removal is messy without pre-cleaning the auger.
Solution: Rinsing the auger head in the clean toilet bowl water during a flush is an easy way to pre-clean the tool.
Tape bunches or unravels when attaching the new faucet.
Solution: Wrapping the tape clockwise prevents it from bunching up or unraveling when you screw on the new faucet.
Overtightened cleanout plugs crack or become impossible to remove.
Solution: Don't overtighten the plastic plug when reinstalling, as it can crack or become difficult to remove later.
Failing to block the drain pipe can lead to tools or debris falling in, causing a significant blockage.
Solution: To avoid this issue: Be mindful of this warning and take appropriate precautions.
Difficulty seating a main line cleanout fitting securely.
Solution: Removing the cap first makes it easier to manipulate the fitting and apply pressure evenly when seating it in the pipe.
Frequently Asked Questions
This project is rated 'intermediate.' How do I know if I'm capable, or if I should call a professional instead?
This project involves working with raw sewage and powerful electric tools, making it intermediate. If you're uncomfortable with the mess, risk of exposure, or operating heavy machinery, it's best to hire a licensed plumber. Consider calling a professional immediately if you suspect a collapsed pipe or persistent recurring clogs.
The guide mentions heavy-duty electric drain augers. Can I use a smaller, hand-cranked auger or a chemical drain cleaner for a main line clog?
For a major main line sewer clog, a heavy-duty electric drain auger is essential. Smaller hand-cranked augers are typically insufficient for the diameter and distance of a main line, and chemical drain cleaners can damage pipes and are ineffective against tough main line blockages. Using the recommended powerful auger ensures enough force and reach to clear the obstruction effectively.
What are the most crucial safety precautions I need to take when working with raw sewage and an electric drain auger?
Always wear heavy-duty waterproof gloves, safety glasses, and old clothing you can discard or thoroughly sanitize. Ensure your work area is well-ventilated and lay down tarps to contain sewage splatter. Use a GFCI-protected outlet for the electric auger to prevent electrical shock, and never touch the rotating cable with bare hands.
What should I do if the auger cable gets stuck or binds while trying to clear the clog?
If the auger cable gets stuck, immediately stop the machine. Try reversing the auger's direction briefly to free it, or gently pull back a few feet before trying to feed it forward again. Never force the cable or continuously run the motor while it's binding, as this can damage the machine or kink the cable.
I'm having trouble locating my main line cleanout. Where are they typically found?
Main line cleanouts are usually located outside your home, close to the foundation, or occasionally in the basement or garage. Look for a cap with a square or hexagonal knob, typically made of PVC, cast iron, or brass, at ground level or slightly above. If you can't find it, tracing the main sewer line from where it exits your house towards the street can help.
After running the auger, how can I be sure the main sewer line is completely clear and the clog won't return immediately?
After retrieving the auger, slowly run water from several fixtures inside the house, like flushing toilets and running sinks, to confirm proper drainage without backing up. Listen for the distinct sound of water freely flowing through the main line. You can also visually inspect the cleanout opening for unimpeded flow before closing it up.
What's the best way to clean up the mess and sanitize the area after clearing a sewer clog?
Collect all solid waste and disposable materials, like tarps and old clothing, and seal them in heavy-duty garbage bags for disposal. Thoroughly clean and disinfect all tools, including the auger cable, with a strong disinfectant solution or bleach water. Scrub the work area with disinfectant to eliminate bacteria and odors.