2:In Vertical water head how much pressure drop in water pipe riser per story 3meter thumb rule?

It depends on the pipe diameter and lesser on the pipe material (negligible).

without going into calculations, as a on-forward answer every 10 meters of pipe vertical elevation need 1 bar (14.7 psi) of water pressure to elevate.

the pressure drop is 

this equation is derived from the original Bernoulli formula

Delta P: pressure drop

L & D: Length of Diameter of pipe

Rho: density of fluid  ( for water = 1000 kg/m^3)

W: fluid velocity ( best between 1.2 m/s and 2.4 m/s to avoid water hammering and to keep it laminar flow)

Presure=weight/area pressure loss through piping for water. Pressure loss due to viscous effect Is proportional to lenght