Ok, My house is pretty old, both my bathtub and toilet drain into our septic tank. Any time water drains out of our bathtub the toilet starts bubbling and when it stops bubbling the water stops drainging and takes a very long time to empty out and we can't flush our toilet during this time. But we can flush our toilet all day long and never have any backup problems till water drains in the tub. HELP ME!! Before I go out of my mind!

U have partial blockage from tub.

Pour vinegar down tub drain before going to bed. Let it stay over night. In morning our about 2 gallons of boiling water down drain.

The vinegar will loosen up hair in pipe and the boiling water will wash out soap scum with hair.

Try this a couple times, if not working u will have to snake the waste line. U would have to remove over flow cap and snake through there.

It could also be the septic tank. When was tank cleaned out last?

Chuck

I agree with Chuck that you have a partial blockage that's sending back pressure back up to the toilet, However I have a different solution.
If the vinegary doesn't work for you then snake the tub from the overflow. (see image).
Unscrew and remove the overflow plate,(The one with the drain lever) and pull out the tub stopper. You now have a clear shot at the trap. The way you were going in through the drain it ran you square into a tee that you can't get around. Now feed the cable( 1/4" best or 3/3" with a small tip. You can rent a Ridgid K50 sink cable.) About 2' down you will run into the bend of the trap. Crank and push at the same time to work around it. Your blockage will be found in the lateral pipe going to the stack. You shouldn't have to put out more then 10 or 12 feet. I have found tub and shower clogs to be mostly hair and the worm should auger into it and pull it back. After you snake pour a few pans of boiling water down the drain. This will loosen the grease and flush the mess out into the main. Hope this helps and thank you for rating my reply. TOM

Ok thank you sooo much! I will try the vinger and if it don't work the snake.
I think the last time it was cleaned out was like 10 years ago.

I agree with chuck but if you mix 1/2 cup backing soda with 1/2 cup salt put it in the drain followed by a cup of vinegar, leave it overnight in the morning try that boiling water as Chuck says, if that would not work try Tom's way and this will work for sure, good luck.

John

Ok thank you so much! The vinegar is in there right now and I am going to pour the water in the morning. If this don't work I will try your way John.