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 toilet bubbles / belch
Author: mr.b (NC)

Have 2 toilets on upper level and 2 on lower level of home. When flushing 1 of the toilets on upper level both toilets on lower level belch air wetting the toilet seats. This does not occur when flushing the other toilet on the upper level. Home is 6 years old and problem did not exist when new but has gotten worse over last 2 years. Problem only occurs with toilet flush and not with sinks etc. No evidence of septic system issues and there is no backup or slow drainage with any plumbing fixture. Plumber inspected clean out from house to septic and noted good flow with no obvious obstruction. Pipe runs down hill from home to tank. We had a radon fan installed on plumbing stink pipe in attic that is attached to radon vent under slab and are not sure if this could have contributed to problem. Have replaced Kohler toilet on main level and still have problem. Would appreciate any suggestions.

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 Re: toilet bubbles / belch
Author: North Carolina Plumber (NC)

The radon vent being connected to the DWV system is definitely a code violation. The air that is being burped up thru the toilets is being trapped in the drainage in somehow. A lot depends upon the layout of the vents or lack thereof. A low spot in the drainage system, or a partial blockage can cause the symptoms as can an improperly designed DWV system.

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 Re: toilet bubbles / belch
Author: PlumberLoren (CA)

Do you have a clean out in the room on the other side of the toilet wall? If not you may need to pull the toilet and snake through the closet bend. If that is not the problem you have a vent that is not sized properly or partially blocked. Can you access your vent on the roof. Take a flashlight up there to see that there is no blockage. If the vent has elbows or 45s in the line you will not see anything. While you are on the roof have someone flush the toilet and put your hand over the vent to see if you feel suction caused by the flush. If you have an attic check to see that the vent has fall so now rain water can fill your vent in the horizontal portion. If you have back fall there it will prevent the vent from doing its job to allow air in to make a good flush. Good luck.

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 Thanks NC Plumber :thumb:
Author: mr.b (NC)

Thanks NC Plumber, Radon fan on vent may be the issue.

Edited 1 times.

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 Re: toilet bubbles / belch
Author: mr.b (NC)

Thanks Plumber Loren,

Will check clean outs first to clear potential obstructions and check venting.

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