Clear streams and bubbling brooks and dreamy waterfalls ... who can resist them? But before you jump in, do check the meteorological report of the area and ask around if it had rained recently. Because no matter how excellent a swimmer you are, when a tonne of debris packed water falls on you, there is no escape.
My cousin in Tapah warned us of "air gunung" whenever we go to splash around in the river behind his house. It's not a particularly big or scarily deep one, but high enough in the mountains to have plenty of rocks to dash one's idiotic head and hapless body upon. So, yeah. Play safe. If someone warns you to get out of the water, for the love of God just go.