The answer to 'shut-off valve leaking water' is that a leaking shut-off valve is a common plumbing issue that can be caused by a variety of factors, such as wear and tear, mineral buildup, or improper installation. Symptoms of a leaking shut-off valve include water dripping from the valve, wet spots around the valve, or even water pooling on the floor.
In many cases, a leaking shut-off valve can be fixed by a homeowner through a simple repair. This may involve tightening the packing nut, replacing the valve's washers or seals, or even replacing the entire valve. However, if the valve is severely damaged or the leak is due to a more complex issue, it's best to call a professional plumber to assess the problem and provide the appropriate solution.