How to stop sewer gas smell from my toilet drain?

 
Identify the Source of the Odor
 

• Determine if the odor is coming directly from the toilet or from another drain in the house.
• Check if the toilet’s water in the bowl is not evaporating, which may lead to the drain pipe losing its water seal.
• Investigate surrounding drain fixtures such as floor drains or sink traps that might be contributing to the sewer gas smell.

 
Ensure the Water Trap Has Enough Water
 

• Confirm that the water-filled P-trap under the toilet and other drains is maintaining its water seal. A missing or insufficient water level can allow sewer gas to escape.
• If you rarely use a floor drain, pour water into it periodically to preserve the water barrier.
• Check for any possible evaporation issues. In dry climates or in a room with low usage, the water may evaporate, necessitating periodic refills.

 
Inspect Seal and Wax Ring
 

• Examine the wax ring seal between the toilet and the floor. A compromised or improperly installed wax ring can allow sewer gases to leak into your room.
• If you suspect the wax ring is deteriorating, consider having a professional re-install it by replacing the old ring with a new one.

 
Verify Vent Pipe Integrity
 

• Check the plumbing vent system that runs to the roof. Blocked or damaged vent pipes can create negative pressure that siphons water out of the trap, opening a pathway for sewer gases.
• Ensure that debris, bird nests, or snow have not obstructed the vent outlet on your roof.
• If you are unsure about the vent condition, hiring a plumber to inspect and clear the vent may be beneficial.

 
Clean the Drain and Surrounding Fixtures
 

• Accumulated grime, biofilm, or debris in the drain can produce unpleasant odors.
• Use a safe, enzyme-based cleaner to eliminate organic materials clogging the pipes.
• Regular cleaning of the toilet bowl, flush mechanism, and nearby fixtures can help prevent odor buildup.

 
Check for Cracks or Structural Damage
 

• Inspect the toilet for any cracks in the porcelain that might be allowing sewer gas to seep out.
• Look for signs of water damage or gaps around the base of the toilet that could indicate the need for repairs or reinstallation.

 
Perform Routine Maintenance
 

• Regularly inspect all drain seals and vent pipes to ensure they function correctly.
• Schedule routine professional inspections if you continue to notice odor issues, as this may indicate underlying problems in the plumbing system.
• Maintain all fixtures with periodic cleaning and preventive measures to ward off potential sewer gas issues.

 
For homeowners in St. Louis and Nashville, these steps can serve as a useful guide in understanding and addressing common plumbing odor issues.