Fixing A Toilet That Is Bubbling And Won't Flush
The gurgling sound of a toilet that won't flush properly puts fear into any homeowner. A toilet that bubbles and fails to clear waste with each flush can quickly lead to messy and costly plumbing issues down the road. When your toilet starts making noises and can't finish the job, it's time to take action.
While a bubbling toilet can seem like a plumbing nightmare, the problem is usually an easy fix. In most cases, a few simple troubleshooting steps and DIY repairs can get your toilet flushing strong once again. Read on to learn what causes toilets to bubble, tips for diagnosing the problem yourself, and step-by-step instructions for finally putting an end to the bubbling and get your toilet functioning properly again.
6 Common Culprits Behind A Gurgling Toilet
Pinpointing the cause of the bubbling is the first step toward getting your toilet to flush fully again. Here are 6 of the most common reasons a toilet gurgles and fails to flush properly:
1. Clogged Toilet
The most common cause of a toilet that bubbles and won't flush is a partial or fully clogged drain line. When excess waste, toilet paper, and other debris builds up in the toilet trap or further down the pipes, it restricts water and waste from flowing freely.
As the toilet struggles to flush against an obstruction, air and water start backing up, causing gurgling sounds from the turbulence. The toilet bubbles as air escapes through water in the bowl. A clogged toilet may still be able to partially drain some of the waste, but will require plunging or snaking to fully clear the blockage.
2. Vent Pipe Obstruction
For a toilet to drain properly, the plumbing system relies on vent pipes that run from the sewer line up through the roof. Vent pipes allow air to enter the system, preventing suction and improving flow. When a vent pipe gets clogged with debris or ice, it can't alleviate air pressure properly.
With no place for air to escape, bubbles start churning in the toilet bowl as air and water collide. Clearing debris from the vent pipe or waiting for ice to thaw will allow normal air pressure to resume and eliminate bubbling issues.
3. Drain Line Trouble
Blockages further downstream in the main sewer drain can also cause a toilet to bubble during flushing. If tree roots infiltrate the pipes, grease and waste accumulate, or sections of drain line settle or get damaged, it restricts the toilet's ability to empty completely.
Sewer gases and air get forced back up the toilet drain as waste tries to exit. This backflow of air leads to gurgling sounds as the air escapes through the toilet water. Professional drain cleaning or repair may be needed to fully eliminate bubbles coming from drain line trouble.
4. Malfunctioning Toilet Tank Parts
Problems with components inside the toilet tank can prevent waste from fully evacuating, resulting in bubbles, burbling noises, and pooled water. Common culprits include:
- A leaking flapper valve allowing water to continuously flow into the bowl
- A broken or misaligned float allowing too much water to enter the tank
- Sediment buildup or deformities on the flush valve seat preventing a proper seal
Replacing worn toilet parts and adjusting components to function properly will often stop unwanted bubbling during flushing.
5. Improperly Installed Toilet
If the toilet base is not properly sealed to the floor, gases and bubbles can escape from the drain line through gaps around the toilet. This often occurs when:
- The wax ring seal has shifted, cracked, or worn away
- The toilet is rocking or improperly secured to the flange
- The floor flange height is not ideal for the toilet
Resetting the bowl on a new wax ring or replacing it with a rubber gasket can eliminate leaks and bubbles between the toilet and floor.
6. Other Plumbing Issues
In some cases, bubbling originating from elsewhere in the plumbing system can travel to the toilet. Trouble spots include:
- Main sewer line clogs forcing sewer gas back up all drains
- A leaky main shutoff valve allowing debris to enter the water supply
- Cracked pipes, allowing water to leak into surrounding soil
- Malfunctioning appliances connected to the plumbing system
If no other toilet fixes resolve bubbling, inspect other components for problems. A professional may be needed to diagnose issues in hidden plumbing.
Quick DIY Troubleshooting Tips
Before calling a plumber, try these fast DIY troubleshooting tips to identify and fix the problem yourself:
Check for a Clogged Toilet
Plunge the toilet vigorously using a plunger designed for toilets to dislodge any obstructions in the trap and drain line. Flush between plunges to see if normal flow has resumed. Alternatively, use a closet auger to snake the toilet drain and scrape away any stubborn clogs.
Inspect the Toilet Tank
Remove the tank lid and flush the toilet, observing all internal components. Look for leaks from the flapper, signs of sediment buildup, and proper float operation. Adjust, clean, or replace any parts not functioning optimally.
Pour Hot Water Down the Drain
Boil several gallons of water and carefully pour down the toilet drain. This melts any accumulation of fat, grease, or other deposits that could be obstructing flow and causing gurgling.
Check Under the Toilet
Inspect the base of the toilet and surrounding floor for water, cracks, damage, or rocking that could indicate an issue with the wax ring seal. Gently rock the toilet to check for movement against the floor.
Look Down Toilet Drain
Use a flashlight to look down into the toilet drain as far as visible. Check for any obstructions, buildup, or misalignments indicating a partial clog.
How To Repair A Sticking Flush Valve
If plunging and snaking don't solve the problem, a malfunctioning flush valve assembly could be causing bubbles and flushing issues.
Remove the tank lid and lift the flapper to inspect it. Look for any cracks, mineral deposits, warping, or damage preventing it from sealing properly. Clean or replace the flapper valve as needed.
2. Check the Seal
Flush the toilet and observe how the flapper seats against the flush valve opening. Look for gaps, leaks, or poor contact indicating a faulty seal. The flapper should evenly seal the entire flush valve mouth.
3. Adjust the Chain
disconnect and reconnect the chain linking the flapper to the flush handle. Adjust it to have about 1/2 inch of slack when the flapper is closed so it seats properly.
4. Clean Valve Seat
Check the flush valve seat for any debris, mineral buildup, or irregularities that could prevent an airtight seal. Clean or smooth away any problem areas.
Unclogging Persistent Drain Line Clogs
For difficult clogs further down the pipes, more aggressive measures may be required to restore proper flushing power:
For clogs close to the toilet, insert a closet auger 3-6 feet down the toilet drain. Rotating the auger will hook and break up the blockage so it can flush through.