Alternative Cistern idea

Dr. John Leininger of Harvest International has been bringing teams down to Haiti for about 30 years, I believe. He works just up in the mountains at the edge of Pestel in a village called Joly Gilbert [on the map below it is south of Deze...To give you some perspective, the distance from Deze to Joly Gilbert in a straight line is 2 miles, but that is a LOOOOONGGGG two miles]


He recently sent me this photo of a cistern that they've put in place:

The setup seems to work quite well, and a real bonus is that it has a spigot (I thought it was 'spicket' but apparently that's not a real word)--one of the main ways the water becomes contaminated is when a dirty pale is placed into the water...contaminating the whole water supply.

The cost is substantially less than that of the concrete/block cisterns. Dr. Leinginger got them for about $400...including the PVC piping.

Does anyone have any thoughts about this construction? See any potential pitfalls? Any suggestions for improvement?

Also, any ideas of how many gallons this would hold?