The answer to 'why is my toilet leaking water' is that there are several common causes, including a worn flapper, a loose toilet tank, or a cracked toilet bowl. Symptoms can include water pooling around the base of the toilet or water dripping from the tank.
Some common solutions include replacing the flapper, tightening the tank bolts, or repairing or replacing the entire toilet. While some minor toilet leaks can be fixed with a DIY approach, it's generally best to call a professional plumber if the leak persists or you're unsure of the cause.