What gauge pressure in the water mains is necessary if a firehose is to spray water to a height of 21 m ?

Height of the water in firehose is 21 m.

Pressure $\"\"$ .

$\"\"$ is the density of water $\"\"$ .

$\"\"$ is the acceleration due to gravity $\"\"$ .

$\"\"$ is the height.

$\"\"$

\"\"

$\"\"$

Pressure is 2.03 atm.