What is the pressure loss per foot of elevation gain?

The pressure loss per foot of elevation gain is commonly calculated using the principle that water pressure decreases as it is lifted against the force of gravity. Specifically, for water, the average rule of thumb is that there is approximately a pressure loss of 0.433 psi for every foot of elevation gain.

This value comes from the relationship between pressure and elevation in fluid dynamics, where one atmosphere of pressure (about 14.7 psi) supports a column of water approximately 33.9 feet high. When you break it down, each foot of vertical rise equates to roughly 0.433 psi.

Understanding this principle is critical in irrigation design and troubleshooting, as it helps technicians determine how much pressure will be available at various elevations in a system, crucial for ensuring that all areas of an irrigation system receive adequate water supply.