The hot water seeps from the surface of the ground into the stream that flows down through a shady forest. The most popular part of is it extremity with the small waterfall flowing into Khlong Thom canal. Besides the small waterfall, there is also a swimming pool, a place that they call a spa but which looks more like a kind of jacuzzi basin. There is even a massage parlor next to the hot waterfall!
The small trail along the hot stream is quite nice to do and leads directly to the waterfall. If you're lazzy, you can can take the tram that connects the Hot Springs entrance to the Hot Stream (400m) for 20 THB.
People often combine the visit of Krabi Emerald Pool with Namtok Ron Khlong Thom which can be found under the name Hot Stream Krabi on GoogleMaps.