Why does the toilet bubble when you turn water on in tub?

The toilet bubbling when you turn on the water in the tub is often caused by air trapped in the plumbing system. When you turn on the water, the pressure in the pipes increases and the air bubbles are forced out. These air bubbles can then travel through the pipes and into the toilet, causing it to bubble.

There are a few things that you can do to try to prevent the toilet from bubbling:

* Make sure that the toilet bowl is properly sealed. If the seal is broken, air can leak into the bowl and cause it to bubble.

* Check the water pressure in your home. If the water pressure is too high, it can cause air to be forced into the pipes and cause the toilet to bubble.

* If the bubbling is only happening when you use the shower or bathtub, try running the water at a lower pressure.

* If you have tried all of these things and the toilet is still bubbling, you may need to call a plumber to take a look at your plumbing system.