Calculating Precipitation Rate
Precipitation rate (PR) is a calculation of the flow rate (application rate) over the square footage of the zone.
Let's break down the equation:
PR = (96.25 * Q) / A
96.25 = constant that converts gallons per minute (GPM) to inches per hour. It is derived from 60 minutes per hour divided by 7.48 gallons per cubic foot, times 12 inches per foot.
Q = gallons per minute (GPM)
A = zone square footage (area in ft2)
For further reading and examples of formula application, go here.
Feel free to check out one of our Rachio Power User's Drip Emitter Calculator for Precipitation Rate here. It's a Rachio Community favorite!