Kanchanaburi located 2 hours drive from Thailand's capital of Bangkok forms the base for a number of outdoor pursuits, though most are drive-in / arm-chair pursuits. There are a number of hot springs and waterfalls, lakes and rivers to be viewed / experienced. More importantly there is a good selection of accommodation throughout the province.
Pha Tad (or Pha Tat) is located well upstream of Kanchanaburi town, 140 km actually. To get there, take Highway 323 towards the Burmese border and turn between km 105 and 106 towards the same direction as Hin Dat Hot Spring and continue for some 10 km further. Pha Tad is located in a national park (Kheaun Sri Nakarin National Park).
After the entrance the is large parking area, facilities (incl. a canteen) and a large grassy area. Beyond that there are two forks with waterfalls, where the water thunders between the forest. When we visited (August 2009) it had just rained a lot so maybe that was the reason of the thunder.
Probably one could plunge/shower around.