One Toilet Keeps Backing Up

Quick answer

To fix a toilet that keeps backing up, start by using a plunger to clear minor clogs. If that fails, use a toilet auger to break up deeper blockages. If the problem persists, check the main sewer line for a more serious blockage.

Confirm the symptom

• Only one toilet is backing up
• Other drains in the house are working fine
• The backup happens after using the toilet

Tools and prep

• Toilet Plunger
• Toilet Auger
• Rubber Gloves
• Bucket
• Plumbing Snake
• Wet/Dry Vacuum
• Screwdriver
• Pipe Wrench

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Prep & safety

• Turn off the water supply to the toilet by closing the shut-off valve located behind the toilet.
• Wear rubber gloves to protect your hands from germs and waste.
• Place a bucket nearby to catch any overflow or water during the process.

Step-by-step troubleshooting

1. Use a Plunger
   Do: Firmly press the plunger over the drain hole and create a tight seal. Push down slowly and then pull up quickly to create suction.
   Observe: Water level in the toilet should decrease and the clog may be cleared.
   Means: The clog was minor and the plunger was able to dislodge it.
   Next: If the toilet is clear, flush it a few times to ensure it works properly.
2. Use a Toilet Auger
   Do: Insert the auger into the toilet bowl and push it down until you feel resistance. Rotate the handle to break up the clog.
   Observe: You may feel the clog breaking apart or see water recede.
   Means: The clog is deeper in the drain line and the auger is effective in clearing it.
   Next: Pull out the auger and flush the toilet to see if the clog is cleared.
3. Check for Main Sewer Line Blockage
   Do: If the toilet continues to back up, check other drains in the house for slow drainage. Use a plumbing snake to clear the main sewer line if necessary.
   Observe: Other drains may also be slow or backing up if the main line is blocked.
   Means: The blockage is likely in the main sewer line and may require professional help.
   Next: If the main line is blocked, consider calling a professional plumber.
4. Inspect Toilet Trap
   Do: Remove the toilet from the floor and inspect the trap for any visible blockages or damage.
   Observe: You may find a blockage or damage in the trap that needs to be cleared or repaired.
   Means: The trap is blocked or damaged, causing the toilet to back up.
   Next: Clear the blockage or replace the trap if necessary.
5. Use a Wet/Dry Vacuum
   Do: Set the vacuum to the wet setting and attach a wet/dry vacuum hose to the toilet drain. Turn on the vacuum to suck out any remaining water and debris.
   Observe: Water and debris should be sucked out of the toilet bowl.
   Means: The vacuum is effectively removing water and debris from the toilet.
   Next: Flush the toilet to ensure it works properly after using the vacuum.
6. Check for Ventilation Issues
   Do: Inspect the roof vent for any blockages such as leaves, debris, or animal nests.
   Observe: You may find a blockage in the roof vent that is causing poor drainage.
   Means: A blocked roof vent can cause slow drainage and backups in the toilet.
   Next: Clear the blockage from the roof vent to improve drainage.

Common causes

Parts you might need

When replacing parts for a toilet that keeps backing up, ensure you match the following specifications:

• Toilet plunger: match the size of the toilet drain hole
• Toilet auger: match the length and flexibility needed for your toilet's drain line
• Toilet trap: match the size and shape of the existing trap
• Roof vent cleaning kit: match the size of the roof vent pipe
• Toilet installation kit: match the size and type of your toilet

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Measure the size of the toilet drain hole and existing parts before purchasing replacements to ensure a proper fit.

When to call a professional

• The toilet continues to back up after using a plunger and toilet auger
• Multiple drains in the house are backing up, indicating a main sewer line blockage
• You suspect tree roots are causing the blockage
• You are unable to clear the blockage with a plumbing snake
• You notice a foul odor coming from the toilet or drains
• The toilet trap is damaged and requires replacement
• You are unsure about how to safely clear the blockage or inspect the main sewer line

FAQ

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