Report: Addition of Rain Bird PRS

15% Savings

Date published: May, 2013


Measure the water consumption and efficiency of an existing rotor system before and after the addition of Rain Bird Pressure Regulating Stems (PRS).

Performed by:

AQUASave Inc.


  • The test zone for this audit was a southward-facing slope with established drought-tolerant trees, shrubs and groundcovers.
  • After a control test, the shrub risers were fitted with Rain Bird PRS devices spaced approximately 40 feet apart at the top of the slope, using the same heads and nozzles.
  • System efficiency was evaluated using two standard irrigation measurement methods: Distribution Uniformity (DU) and Scheduling Coefficient (SC). High DU readings reflect more even coverage of a zone. A lower Scheduling Coefficient means a shorter run time was necessary to water a zone properly.



The pre-audit segment of the test was performed on the existing irrigation system components without the PRS and resulted in the following system observations:

Pre-Audit Control Test
System Efficiency (DU) 43%
Scheduling Coefficient 5.2
Flow rate 29.6 gpm
Volume of water used for test 553 gallons

Post Audit:

Following the pre-audit the shrub risers were fitted with the Rain Bird PRS devise using the same heads and nozzles as the control test of the pre-audit. The results were:

Post-Audit Test #1 Test #2
System Efficiency (DU) 55% 58%
Scheduling Coefficient 1 1
Flow rate 27.4 gpm 27.4 gpm
Volume of water used for test 512 gallons 513 gallons

Findings Summary:

Audit Performance Summary
Test #1 Test #2
System Efficiency (DU) 13% (better) 15% (better)
Scheduling Coefficient 82% (better) 82% (better)
Flow rate 7.4% (better) 7.4% (better)
Volume of water used for test 7.2% (better) 7.2% (better)


After adding PRS to existing rotor system:

  • Distribution Uniformity (DU) increased.
  • Scheduling Coefficient (SC) was lowered.
  • Water consumption was reduced.