To calculate the water pressure in pounds per square inch (psi) for a given height in feet (ft), you can use the following formula:

Water Pressure (psi) = Height (ft) / 2.31

In this case, for a height of 900 ft, the water pressure would be:

Water Pressure (psi) = 900 ft / 2.31

≈ 389.61 psi

Therefore, the water pressure for 900 ft is approximately 389.61 psi.