It is one of the most famous waterfalls near the city of Chiang Rai. Located 25 km on the mountain Doi Hang, you can reach it by a small trail (about twenty minutes) in the forest. You can bath there but not really swim, it's always nice to cool off but the bathing area is limited. There is water all the year even though the flow is lower at the end of the dry season (March-April).
There are 2 paths to get to the waterfall, one of them passes through a small Akha village (with several guesthouses). It may be interesting to go int he village after the waterfall. On the way to and back from Huay Kaew Waterfall, you can stop at a hot springs for a moment of relaxation, Huai Mak Lium Hot Springs or the Phra Soet Hot Springs and its mineral water pool are not that far.