How do I calculate my precipitation rate?

Calculating Precipitation Rate

Precipitation rate (PR) which is a calculation of the flow rate (application rate) over the square footage of the zone.

Let's break down the equation for everyone to better understand:

PR = (96.25(A * B)) / (C)

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.
A = # of heads -or- # of emitters
B = flow rate (GPM) per head -or- emitter
C = zone square footage


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!

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