Cistern Capacity:

Our cistern will be 1 meter underground sandstone permitting. And above ground for another 1 meters. The area will be 4 meters by 2.5 meter, square. It will contain rebar in every hallow block, and a horizontal in each of the 10 layers. 10 mm deemed good enough and is standard here. Finishing will be done with Sahara cement. This volume gives us 20 cubic meters, or 20,000 liters. We can already see that one heavy rain will fill it completely or at least within one week of little rain!!