The answer to 'why is my drain leaking water' is that a leaking drain is typically caused by a plumbing issue, such as a crack or break in the pipe, a loose connection, or a clogged drain. Symptoms of a leaking drain include water pooling around the drain, water stains on the floor or walls, and a damp or musty odor. Possible solutions include tightening connections, replacing washers or gaskets, or clearing a clogged drain.
If the leak is minor and you feel comfortable doing so, you may be able to fix it yourself with some basic plumbing tools and supplies. However, for more serious or complex issues, it's best to call a professional plumber who can properly diagnose and repair the problem to prevent further damage to your home.