If the question ever cam to mind as to calculate the PSI found in the top chamber of a Berkey water system, then the following calculation would apply.

This calculation determines the PSI found at the base of the Black Berkey Purifier Element and decreases as it nears the top, obviously complementing the basics principal that the filling speed is always faster with a full head of water.

How to Translate the Height of a Column of Water to Pressure or PSI

Since water is virtually non-compressible, its density doesn't vary by height. And we can ignore width or diamater of the water pipe or well casing too. Only the height of the column of water matters.

The pressure exerted by a vertical column of water inside of a well casing or a pipe, measured at the bottom of that column, is determined as follows:

The pressure of a column of water is about 0.433 psi per foot of column height

We calculated this psi above by dividing the weight of a cubic foot of water by the number of square inches in the bottom of the cubic foot: (62.4796 / 144 sq.in) = 0.433 pounds per square inch or psi.

That's for water at 32 °F. If warm the water up it will weigh a little less - the actual weight of water varies slightly by temperature as its density varies by temperature and possibly also by the effect of impurities in the water.

1 ft of water produces 0.433 psi of pressure at the bottom of that column [re-stating the information just above]

So the formula for the psi pressure of a column of water is

PSI of water pressure at the base of a column of water of height H in feet = H x 0.434

Calculation Reference  + PSI to Foot

 

Royal Berkey 12.3 ltr unit top chamber is 11.41 inches deep .95 of a foot (12 inches)

H (.95) x 0.434 = .4123 PSI