You can find the water tanks by following the signs. Green plants, birds, animal tracks, fecal matter, and bees. With one hiking group we searched all day and never found the tenaha we were looking for. The next week we went out with Chuck, a museum trustee, and we found six or seven in a small amount of time.
There is also the tale tell sign that you are near a traditional tenaha that has been used historically as a water source in the desert - broken pottery.
On the way home we also stopped by the water holes that are used today. Five Palms is a natural warm spring where 92 degree water comes out of the ground and has created a two foot pool of warm water in the middle of the desert.
We spent about 30 minutes soaking in the evening on New Years Day.