Having your toilet bubble and gurgle when someone is using the shower is a common problem that can be annoying and worrisome. Understanding the potential causes can help you address the issue properly.
What Causes Bubbling in the Toilet When the Shower Is On?
There are a few likely culprits for this phenomenon:
Drain Venting Issues
All drains in your home connect and vent together through a main stack vent. This allows air to enter the system so water flows freely. If the vent stack becomes clogged or improperly installed, it can cause pressure differences when one drain is being used. This results in bubbling as air is sucked through the toilet water.
Improper Plumbing Slope
For waste water to drain optimally, drain pipes need proper slope. If installed incorrectly, shower or sink drains may not have enough slope. When water runs through it, air bubbles back up through the toilet.
Clogged Pipes
Partial obstructions in the drain lines can also lead to bubbles in the toilet bowl. As water squeezes past the clog, air is displaced through the toilet water. Clogs from hair, grease, soap scum, and other debris are common culprits.
Sewer Gas
Methane gas production is a natural part of sewage decomposition. If your drain traps dry out, these gases can leak through your drains. Bubbles in the toilet when the shower runs may indicate sewer gas escaping through the water.
How to Fix Bubbling Toilet When Shower Is On
Pinpointing the cause is the first step to treating this bubbling toilet issue:
Check the Vent Stack
Inspect your roof and see if the plumbing vent stack is obstructed or improperly installed. Hire a plumber if needed to ensure proper venting.
Snake the Drain Lines
Use a drain auger to remove any obstructions in the drain pipes. Focus on the shower drain first, then sink and toilet if needed.
Install Proper Plumbing Slope
If drains lack proper slope, a plumber may need to repair or replace sections to fix the issue.
Refill Drain Traps
Pour water down seldom used drains to keep their traps full and prevent sewer gas intrusions.
Install Backflow Valve
A backflow prevention valve installed on the sewer main line can prevent air bubbles from backing up through the toilet.
When to Call a Professional for Bubbling Toilet
While minor drain clogs may be DIY, it’s best to call a plumber for:
- Persistent bubbling indicating venting issues
- Improper drain slope that requires re-plumbing
- Inability to clear clog with drain snake
- Backups or flooding accompanying the bubbling
- Sewer gas smell coming from toilet
A professional can assess the cause and make necessary repairs to restore proper drainage. Ignoring bubbling toilet issues risks bigger problems down the line.
FAQs About Bubbling Toilet When Shower Is On
Why does my toilet bubble when someone is in the shower?
Pressure differences caused by venting problems, clogged drains, or improper slope allow air to be sucked through the toilet trap and bubble up through the water when the shower runs.
Is it safe to use a bubbling toilet?
Minor bubbling from venting or drain issues is generally safe, but sewer gas bubbles can pose a health hazard. Call a plumber if you suspect sewer gas.
Can I use drain cleaner to stop the bubbling?
Chemical drain cleaners are ineffective for fixing these issues long-term. Snaking the drains or calling a plumber to address underlying problems is the proper fix.
Does a bubbling toilet mean my septic tank is backing up?
It’s unlikely, but possible if your main drain vent is severely blocked. Check the roof vent stack first before assuming a septic problem.
How do I unclog my shower drain to stop toilet bubbling?
Use a zip-it drain cleaner, followed by a drain snake if needed. Focus on the shower drain first. You may need to snake the sink drain and toilet as well to clear any obstruction.
Why does my toilet gurgle when someone is in the shower?
Gurgling is the sound of air bubbles moving through the toilet trap. It has the same causes as bubbling and requires drain corrections to address the underlying issue.
Conclusion
Bubbling and gurgling from your toilet when the shower runs can be an annoyance and hygiene worry. Checking your plumbing vents, clearing any clogs, and installing proper drain slope can typically solve the problem. For persistent issues, call a professional plumber to inspect and repair your drains to restore normal function. Addressing this issue promptly prevents bigger problems down the road.
