I am glad I have someone young and strong to climb up and check our water levels. Under that tank are our two bathrooms side by side. The door with the blue steps goes to the boys bedroom. The description is so you can have a little idea of the way our house works.
The only water supply for our entire house is fed by rain water. The rain that falls on the roof travels through gutters and down spouts into a large tank. I wonder if a rainwater collection system would be an option for you.
It would be great during the rainy season, but not so much during the dry season when rain does not fall for about 6 months. Things are actually improving as we have place a pump near the street to push water up to our tank. It still relies on the neighborhood getting water which does not always happen, but usually it does.