A clog happens when sink, toilet, or shower water drain slowly. Clogs can be come so severe that water backs up from where it should drain.
Drips are a running toilet or faucet that continues to run once you have flushed or turned off the water. The solution may be as simple as checking the handles or replacing a washer to calling a professional if the problem is either inaccessible or needs special tools to fix.
Leaks problems in a bathroom can range from simple cracked washers on a sink or bathtub to compression fittings gone awry. Leaks can sometimes be easily fixed, but may require a professional if welding or soldering becomes necessary.
A most likely candidate for the most common bathroom plumbing problem is the clogged toilet. Clogged toilets can generally be fixed with a basic plunger. If the clog is stubborn a closet auger may be needed to loosen the clog.
A problem with plumbing that may cause bathroom flooding is a bad toilet seal. A standard toilet has five seal points. If any of them is bad there might end up being between one and five gallons of water on the floor per flush.