Boy, I'd bet as seldom as humanly possible and a chore that you always want someone else to do. I have been in our McEwen water tank a couple times and it was not real nice with several inches of mud covering the bottom. It is a steel tank however. My first adventure was to take an oxyacetelene torch in and try to reshape the hook on the gate as it had become disconnected. It was very hot and muggy. I had to prop the gate open for a little air. The second time as recall we put a new gasket on the gate and put a bunch of screws into the rusted out pipe that was leaking. I could barely get out both times. Getting out involved putting my arms over large planks across the top of the tank and with my feet dangling in mid air 12' off the bottom of the tank which is 16' feet tall using all the strength a fat boy can summon lift myself over the edge and onto a precarious ladder on the outside. Since my trips inside others have been in it and made improvements. I am quite certain I will not try it again as I have put on a few more lbs. Likely the experience of getting into the Grande's wooden tanks was no less of an acrobatic chore.