When a drain is clogged, water no longer goes through but collects in the shower instead. It is possible to buy a product that is specifically designed to unclog a drain, or you can try using household products. Alka-Seltzer tablets and vinegar may seem like an odd cleaning method, but many people use it for their clogs.
Drop 3 antacid tablets (Alka-Seltzer) down the drain.
Pour 1 cup of white vinegar down the drain.
Wait a few minutes so that the antacid tablets and vinegar can work through the clog.
Turn on the hot water and let it run through the drain to clear out the clog.