The easiest and quickest way to find out where a radiator is leaking water from is to dry down the surface of the device using a towel.
Once the appliance is dry, it will be simple to work out where the radiator is leaking water from; one of three locations. Water leaks will emerge either from the body of the radiator, the pipe that fills it with hot water, or the radiator valve or rad tails.
For a greater insight, explore our dedicated blog, How To Fix A Leaky Radiator.