Great question — answering as the UphillTech team:
The distance from the top of the water level to the faucet determines the pressure at the faucet. 1 meter =1.42 psi, 2 meters=2.84 psi and 3 meters=4.26 psi (not much pressure). Remember you measure from the water level to the faucet, not to the floor. To get more pressure you need to raise the tank or add a pump system. The pipe size has little to do with the delivered pressure, it does however control the volume of flow.
Full answer by d.george: https://diy.stackexchange.com/a/114307 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
