Why does draining my bath tub cause my toilet to bubble?

Answer by  Sockless (528)

Because when you drain the bathtub, it has to force all the air out of the drain pipe. That air will go out of the system the easiest way. In most cases that would be out the pipe into the sewer or a vent pipe, but in some cases, it might be another drain, like a toilet.

Answer by  ajk71486 (219)

This sounds like the vent that allows sewer gas to escape in a non-harmful location is partially or fully blocked. This can allow harmful gasses inside your home and should be repaired asap.

Answer by  Laura47 (138)

Draining your bath tub causes your toilet to bubble because in many houses both the bath tub and the toilet drain through the same pipe. When you drain your bath tub, this pipe reaches capacity, causing water (and bubbles) to go where there is room, in this case, the toilet.

Answer by  pedro (142)

The toilet bubbles because it is connected to the same drain line as your bathtub. If the drain line is clogged or draining slowly, the water has nowhere to go, and since it shares a drain line it will filter back to your toilet. If the clog gets bad enough, your toilet will eventually back up.

Answer by  gshort6228aolcom (30)

This sound occurs when you have a blockage in plumbing pipe from your toilet to the sewer or septic tank and will hear it before a complete blockage occurs with an overflow from the toilet. You will need to snake your drain pipe to dislodge any blockage or call a plumber.

Answer by  LeheckaG (1826)

Normally, there is a sewer gas vent pipe leading from your sewer drains up through your roof. Either your plumber did not install one, or Often small animals (birds, racoons, squirrels, ...) can cause clogs. Without a clear/functioning sewer gas vent pipe: draining your bath tub pressurizes your sewer gas, and the pressurized sewer gas bubbles up through your toilet.

Answer by  Liz59 (10966)

Basically this must be happening if your pipes of the tub and the toilet are interconnected. That is why you will see that.

Answer by  thelostone (1457)

The most obvious cause of this would be a slow draing somewhere in your house. When draining the bathtub your pipes fill with water. IF one of the pipes is partially clogged then the water is backing up and goign in directions it shouldn't one of which is towards your toilet. Have your pipes cleaned out.

Answer by  chespa (82)

In some houses the bath tub and the toilet drain pipes may be connected to the same pipe. If they are connected to the same pipe to much wate in the drain pipe at one time can cause a bubbling effect.

Answer by  Liz59 (10966)

Well it is probably because your drain pipe is connected to the toilet. This indicates some kind of defect with the pipe. You might want to get a plumber to check through this.

Answer by  grothcc (119)

Usually this is a venting problem. The tub or toilet is either not vented properly or at all, or the vent has become clogged.

Answer by  Anonymous

Increase the angle of the large drain pipes under or outside your house leading to the desposal system what ever type that may be.