How much time does it take for my overhead water tank to be filled?

1. To get started you need to know the dimensions of the tank. If you don't know measure it using steel tape or a ruler.

What is the shape of your tank? In my case it is a cylinder positioned horizontally with slight protrusion on both base. There is an added opening hole at the top.

So here are my dimensions. 15.5 inches in diameter and 66 inches long. That's all I need because what I need is to calculate the volume of the tank. The formula for determining the volume of a cylinder is pi(d^2)(h).

2. Next thing I need to know is the flow rate of the water. What I have to do is to neatly funnel up the water input and measure on an empty one liter coke bottle, clock in the time and boom I got the time in seconds per liter of water input.