My bathtub won't drain. Gel drain cleaner did nothing except come back up into the tub. Now I have to scoop it and the water out. When I put water in the bathroom sink, it drains but the water level in the tub rises. Both are upstairs in the same room. The toilet in the same room flushes but the water level in the tub does not change when it is flushed. The kitchen sink drains (I don't think it causes the tub water level to rise). In fact, the tub water level rises when I don't seem to be using water anywhere else! Any ideas? Where could the water be coming from?

The drain from your sink and tub come together and are blocked prior to the toilet. Remove the overflow plate from the tub and rod there or remove the sink trap and rod into the verticle pipe from the wall. Stop with the chemicals and do the rodding.

Bob nailed it! Unscrew and remove the overflow plate,(The one with the drain lever) and pull out the tub stopper.(see image) 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 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 snake should auger into it and pull it back. Hope this helps and thank you for rating my reply. TOM