PRS Advantage

4 Easy Steps to Water Savings

Estimated Water Savings Analysis for a Rain Bird 1800-PRS Upgrade

Rain Bird’s patented 1800 PRS in-stem pressure regulator ensures maximum spray head and nozzle performance, even with varying inlet pressures. By maintaining constant optimum pressure of 30 psi at the nozzle, 1800 PRS spray heads end misting and fogging caused by high pressures. For you that means water savings. Enter the information from your system below and see how much water you can save!

See How This Formula was Derived

PRS Formula Details

The Values in this chart were derived from Bernouli’s equation (5.19). Please refer to Roberson/Crowe, Engineering Fluid Mechanics (Fourth Edition), Houghton Mifflin Company, Boston MA, 1990.

PRS-Chart In the chart to the left, Bernoulli’s equation was utilized to calculate the potential Water Savings Multiplier. This Multiplier represents the fraction of water that could be saved by operating standard spray heads at 30 psi.

Bernoulli’s equation is used in engineering to predict fluid pressures within a body (for example, water pressures in an operating spray head). As these pressures change within a spray head, the spray pattern changes, resulting in less efficient utilization of the water flowing through the spray head.

Enter the pressure (psi) at the nozzle here:
(Either enter the average dynamic pressure for the spray heads on one zone or enter the average dynamic pressure for all the spray heads on the entire system. If the dynamic pressure is not available, enter the system's static pressure. The static pressure will overstate the water savings, but it will still provide an estimate of the potential water savings.)
Enter the GPM @ 30 psi here:
(If you entered the pressure for one zone above, enter the GPM for that zone. If you entered the pressure for the entire system above, enter the GPM for the entire system).
Average Watering Time per Day (min.):
Average Number of Watering Days per Week:
Average Watering Weeks per Year:

The initial system waste is:		GPM
The yearly water savings is:		gallons *

* Due to varying conditions, your actual water savings may be different. This formula is designed solely as a basis for estimating potential savings.