The answer to 'why is my P-trap leaking water' is that the P-trap is likely not installed properly or has become damaged over time. The P-trap is the U-shaped pipe under your sink that is designed to hold water and prevent sewer gases from entering your home. If it is leaking, it could be due to a cracked or loose connection, a worn-out gasket, or improper installation.
Some common symptoms of a leaky P-trap include water pooling under the sink, musty odors, and water damage to the cabinet or floor. To fix a leaky P-trap, you may need to tighten the connections, replace the gasket, or in some cases, replace the entire P-trap. If you're not comfortable doing this yourself, it's best to call a professional plumber to diagnose and repair the issue.