There are two types of waterspouts, tornadic and non-tornadic. Tornadic waterspouts are simply tornados that have moved over water. Non-tornadic spouts form differently than their tornadic counterparts are much weaker and slower.
Waterspouts are measured on the Fujita scale (F-Scale), the same as tornados.
“Waterspouts are common along the southeast U.S. coast, especially off southern Florida and the Keys and can happen over seas, bays, and lakes worldwide. Approximately 160 waterspouts are currently reported per year across Europe, with the Netherlands reporting the most at 60, followed by Spain and Italy at 25, and the United Kingdom at 15.”
And if they aren't complicated enough, there's also the winter waterspout.
“A winter waterspout, also known as a snow devil, an icespout, an ice devil, a snonado, or a snowspout, is an extremely rare meteorological phenomenon in which a vortex resembling that of a waterspout forms under the base of a snow squall. The term "winter waterspout" is used to differentiate between a common warm season waterspout and the rare winter season waterspout which will often form in temperatures of −18 °C (−0.4 F) or colder. Very little is known about this rare phenomenon and only six known pictures of this event exist to date, four of which were taken in Ontario, Canada.”