Why Is My Toilet Bubbling and How Do We Stop It?

If you've noticed gurgling noises or bubbles coming from your toilet, you're not alone. Bubbling toilets are a common problem many homeowners face. While the bubbling may seem harmless at first, it often signals an underlying issue that needs attention.

By understanding the root of the problem, you can take the proper steps to repair your toilet and prevent future bubbling and backups.

What Causes Bubbling in the Toilet?

There are a few common culprits behind a bubbly toilet:

Clogged Toilet Trap or Drain

A clog in the toilet trap or drain pipe is one of the most common causes of a gurgling commode. When waste and debris get stuck in the trap or drain, it blocks the free flow of water. The backup causes air bubbles as water attempts to drain past the blockage.

Clogs occur when too much toilet paper or other objects like toys or wipes get flushed. A buildup of mineral deposits and grime can also cause a gradual blockage over time. Clearing the clog is the only way to stop the bubbling caused by a blocked toilet trap or drain.

Blocked Main Vent Stack

The main vent stack in your home provides proper air circulation to drain water and sewer gases out of the pipes. If the roof vent becomes clogged with leaves, nests or other debris, it can't vent gases as efficiently.

This causes air to get sucked through traps as water drains, creating bubbles, gurgles and slow drainage. Unclogging the main vent stack or adding an auxiliary vent can solve this issue.

Main Sewer Line Clog

A partial or full clog in the main sewer line leading from your home to the public sewer main can also cause bubbling from toilet drains. As other fixtures like showers or sinks drain, excess water gets forced down the main line, displacing the clog and bubbling up through the toilet trap.

Sewer line clogs often require professional drain cleaning with high-pressure water jets or mechanical augers to fully clear. Repiping may be needed if the line is damaged or persistently clogs.

Unlevel Toilet

If the toilet base rocks or wobbles, it likely isn't sitting flush with the floor. This uneven installation prevents the trap from properly sealing, allowing air and water to mix in the drain pipe and bubble up into the bowl.

Reseating the toilet on a new wax ring or adding shims can effectively level and stabilize the base to prevent further bubbling from this issue.

Excess Air in Toilet Tank

Too much air entering the toilet tank can also lead to bubbles. Each flush allows high-pressure air to flow into the tank. Over time, excess air accumulates and gets released down into the bowl while draining, causing gurgling noises.

Bleeding the air pocket from the tank and adjusting the water level solves most tank air problems. Faulty fill valves or improper venting allows air to leak in, requiring replacements.

Old Corroded Pipes

In older homes with corroded or deteriorating pipes, cracked fittings and loose joints allow air to seep into the drain lines. This leads to bubbles, gurgles and reduced water pressure from the added air.

Updating old drain pipes and supply lines reduces leaks and air pockets. But this does require opening walls for access, so have a plumber inspect and provide pipe replacement quotes.

High Water Pressure

Excessively high water pressure entering your home's plumbing system can also cause bubbles in toilet bowls and drains. Too much pressure strains fittings and valves, allowing air intrusion.

Installing a pressure reducing valve and regulating water pressure between 50-60 PSI prevents surges that introduce air into your drains. This eliminates bubbling toilets from high pressure.

Frozen Pipes

In cold climates, frozen pipes are a common winter problem that can lead to bubbling drains. When water in pipes freeze and expand, it displaces air that gets forced through taps and drains as ice blockages melt.

Insulating exposed water pipes, sealing drafts in your home, and allowing taps to slowly drip during sub-freezing weather can prevent frozen pipes and related bubbling issues.

Tree Roots in Sewer Line

Over time, tree roots can invade and clog sections of your main sewer line. As roots permeate the pipe, they displace water flow, causing bubbles, gurgles and slow drainage.

Specialized sewer augers combined with root killer chemicals can clear root blockages. Severely damaged lines may need partial replacement where roots have fully penetrated the pipes.

Septic Tank Issues

Homes on a septic system can experience bubbling toilet drains when the septic tank gets overfilled and waste backs up into pipes. Septic backups indicate it's time to pump out the tank.

Slow drainage between pump outs hints at a problem with the leach fields or clogged inlet/outlet pipes. Have a septic contractor inspect these issues to prevent sewage backups.

Signs of a Clogged Toilet Trap

Noticing these signs point to a clog in your toilet trap as the culprit behind the bubbles:

• Gurgling noises only during flushing
• Toilet takes longer to empty after flushing
• Bubbling and draining issues in just one toilet
• Toilet doesn't fully empty all water out after flush

A clogged toilet trap prevents the free flow of water and air, leading to bubbles and reduced flow. Tackling the clog is key to stopping the bubbling.

How to Unclog the Toilet Trap

Several DIY methods can clear out a clogged toilet trap:

Use a Plunger

Plunging creates suction that can dislodge clogs. Place a plunger over the drain hole forming a tight seal. Quickly push and pull the plunger to loosen the blockage without removing water from the bowl.

Try a Closet Auger

For stubborn clogs, insert a closet auger (or toilet snake) down the drain past the trap to break up and hook debris. Slowly twist and rotate the auger to clear obstructions.

Remove Toilet and Inspect Trap

Removing the toilet gives full access to the trap. Check for clogs and use wire hooks or an auger directly in the exposed pipe to clear blockages.

Clear Clogs Manually

Wearing gloves, you can attempt removing the clog by hand with thick cloth or paper towels. Remove remaining water from the bowl first using a cup or sponge.

With the trap clear, flushing bubbles caused by a clogged toilet should stop.

Signs of a Blocked Main Vent Stack

A clogged main vent stack often causes:

• Bubbling drains throughout the entire house, not just one toilet
• Gurgling noises emanating from roof vents
• Very slow drainage of sinks, tubs and other fixtures
• Sewer gas smells from drains

Since all drains connect to the main vent stack, a blockage here impacts the whole drainage system, not just one toilet. Getting the vent working properly keeps air flowing.

How to Clear Clogged Vents

Here are some DIY and professional methods to clear vent obstructions:

Inspect Roof Vents

Climb on the roof to check for debris blocking the vent pipe openings. Remove any nests, leaves or other material clogging the vent.

Clear Debris From Vent

Use a wire hook from the top to fish out and dislodge clogs. Run a hose down the vent to flush out debris.

Have Vent Snaked by Plumber

For deep vent clogs, professional drain cleaning snakes can clear out the blockage from the roof.

Replace Damaged Vents

Badly corroded vents should get replaced to prevent recurring clogs and ensure proper air circulation.

With vents cleared, air bubbles in drains caused by venting issues will be eliminated.

Signs of Main Sewer Line Clogs

Main sewer line clogs reveal themselves through:

• Bubbling toilet when sinks, showers or tubs drain
• Backups of wastewater into showers, bathtubs or basement sinks
• Very slow drainage of all fixtures in the house
• Sewer gas odors around cleanouts and drains

Clogs in the main sewer line affect your entire plumbing system's drainage. Professional assistance is often required to fully clear obstructions.

How to Address Mainline Clogs

Try Drain Cleaning Chemicals

Liquid drain cleaners and enzymes can help dissolve organic matter and grease clogging the main line. Follow product instructions carefully.

Use a Sewer Tape

Feeding a flexible sewer tape down the line lets you measure the distance to the clog. This can help plumbers determine cleaning equipment needed.

Call a Plumber for Drain Cleaning

For severe mainline clogs, call a professional plumber. They have high-pressure water jetting equipment and mechanical drain snakes to clear blockages.

Camera Inspection

A camera scoped down the sewer line lets plumbers visually identify blockages and see any damage needing repair.

Completely clearing clogs and fixing damaged lines provides lasting solutions to mainline bubbling issues.

How to Fix an Unlevel Toilet

Here are tips on leveling a wobbly, rocking toilet:

Check if Toilet Rocks

Look to see if the toilet rocks when you press alternately on the bowl sides. Grab the bowl and see if you can wiggle or shake the base.

Reseat the Toilet on New Wax Ring

Lifting the toilet to reseat it on a fresh wax ring typically solves most loose toilet problems. Sitting unevenly allows air and water to mix in the trap.

Use Shims to Level Toilet

Leveling shims placed under the toilet base fill any gaps between the flooring and toilet feet to prevent rocking and bubbling issues.

Ensure Floor is Not Uneven

An uneven bathroom floor can prevent the toilet from sitting flush. Inspect if the floor is sagging and level if needed.

A properly seated toilet shouldn't rock or move, eliminating bubbling issues.

Bleeding Excess Air from the Toilet Tank

To eliminate bubbling from excess air in the toilet tank:

Jiggle the Fill Valve

Jiggling the float and fill valve allows trapped air bubbles to release into the tank. Repeat a few times to bleed the air pocket.

Adjust the Tank Water Level

Make sure the tank water level is set correctly, about 1/2 inch below the overflow tube opening. This prevents air from entering the flush valves.

Replace the Fill Valve

If old or faulty fill valves are allowing too much air into the tank, replacing the entire fill valve assembly can improve operation and reduce bubbles.

With excess air removed from the tank, bubbling and irregular flushing should be eliminated.

Fixing Issues With Old Pipes

Common solutions for problems with old drain pipes include:

Inspect Pipes for Leaks

Check under sinks and along walls for water stains indicating leaks in old pipes. Feel for moist spots behind walls where pipes run.

Have Old Pipes Replaced by Plumber

Severely deteriorated old pipes allow air to enter the plumbing system. A professional repiping of the drain lines eliminates leakage and bubbles.

Use Pipe Sealant on Small Leaks

Applying quality pipe sealants or epoxies can seal small holes and cracks in old pipes, preventing additional leakage issues.

Upgrading old drain pipes reduces air intake and bubbling toilet problems over the long run.

Adjusting Home Water Pressure

To adjust excess water pressure causing bubbles:

Identify High Pressure

Pressure above 80 PSI strains plumbing and introduces air. Attach a pressure gauge to an outdoor spigot to get a reading.

Install a Pressure Reducing Valve

A PRV valve regulates water flow into the home. Have a plumber install one if over 80 PSI.

Set Pressure Between 50-60 PSI

The PRV valve can be adjusted as needed to reduce pressure down to a range of 50-60 PSI to prevent plumbing issues.

Controlling water pressure prevents strain and air intrusion leading to toilet bubbles.

Preventing Frozen Pipes

To avoid frozen pipes and bubbling drains:

Insulate Exposed Pipes

Insulating exposed water pipes in basements, attics and crawl spaces helps prevent freezing in cold weather.

Seal Air Drafts

Sealing cracks, windows and doors prevents cold outside air from reaching vulnerable pipes and causing them to freeze.

Let Faucets Drip

Allowing faucets to slowly drip during sub-freezing temperatures keeps water moving in the pipes, stopping freeze-ups.

Keep Thermostat Above 55degF

Maintaining heat in your home at 55degF or higher reduces the risk of pipes freezing during winter months.

Taking preventative measures guards against frozen pipes, protecting your plumbing from freeze-related bubbling.

Removing Roots From Sewer Line

Tree root invasions can be removed from the sewer line using:

Sewer Augers

Mechanical drain snakes with cutting heads slice through roots when twisted down the line.

Root Killer Chemicals

Foaming root killers help dissolve roots and inhibit regrowth. They're poured down the drain.

Replace Damaged Sections

Badly penetrated sections may need replacement to fully remove invasive tree roots from the sewer line.

Vigilant root removal provides lasting relief from bubbling drains caused by root intrusions.