In SaPa there is a lot of fuss about taking a walk to Cat-Cat village, about 3 kms from the centre of town. It doesn't seem very far, but I'm not sure where the village actually is. There is a winding track down with a toll booth, houses along the way selling the usual stuff (and even a bit of a forge). Down at the base, there are lean-tos which are selling food and tea, and this is where the waterfall was. The track follows the river, then climbs back up to Sa Pa. There had been a good bit of rain in the 24 hours prior to our arrival, so the fall, a minor affair when I visited in DEc 2007, was a bit more misty and muddy.