Water pools in the shower because it can’t escape down the drain, usually due to some sort of blockage. Hair, dust, and soap scum are the most common causes of shower drain blockages. In some cases, you can remove the drain grate and pull out the hair using a pair of gloves. If the clog is deeper, a metal coat hanger may be able to help you. If you can’t reach the clog yourself, consider calling Drain Blast for professional assistance.