Clear Marine Vinyl Sheet On Bathtub Surround To Temporarily Waterproof Walls?
That sounds like a longer lasting solution than duck-taping a couple of shower curtains up. Remember that a shower curtain protects the floor outside the tub from getting wet, so I'd think this should work just fine as a one-year-or-so &quot;temporary&quot; solution.

Make sure that you overlap the sheeting onto the surface of the tub. It could be that there is an unsealed grout joint way down low and that the grout is wicking the water up and over the lip of the tub that's sitting behind the tile.
Make sure the adhesive you choose is suitable for the sheeting you're using. I'm not certain whether or not your particular choice is good or not, just giving you a reminder.

I put &quot;temporary&quot; in quotes because sometimes these things drag on... ;)