The answer to 'drain overflowing' is that there are several common causes, including a clogged drain, a blockage in the sewer line, or a problem with the plumbing system. Symptoms of an overflowing drain can include water backing up in the sink, bathtub, or toilet, and a foul odor coming from the drain. Solutions may involve using a plunger, a drain snake, or chemical drain cleaner to clear the clog, or calling a professional plumber to diagnose and fix the underlying issue.
It's important to address an overflowing drain promptly, as it can lead to water damage and potentially hazardous conditions. If the clog is minor and you feel comfortable using a plunger or drain snake, you can try a DIY solution. However, if the clog is severe or you suspect a problem with the sewer line or plumbing system, it's best to call a professional plumber to diagnose and fix the issue.