Will You Be Performing an Irrigation Audit?
Irrigation Water Audit
This page is designed around calculations I use to perform an irrigation audit. This is simply to give you a guideline for water usage and is by no means perfect.
Enter the throat area in square inches for your catch cups (all the catch cups need to be the same for the test to be accurate). This allows you to use any size container measuring less than a foot across as long, as you know the throat area in square inches (opening through which the water enters). You will also need a way to measure the volume in milliliters. There are specially designed catch cups for this purpose, as seen in the picture.
This is one of the least expensive catch-cups available.
This is an example of how to set up the catch cups for an audit. The blue dots represent sprinkler heads and the red dots represent the catch cups.
Run time in minutes for this test.
Enter the amount from each catch cup in milliliters. You must use at least 4 catch cups.
Catch Cup Totals
The distribution uniformity is calculated and updated for every 4 catch cups inputted.
Use sprinkler efficiency from the catch cups test?
Enter Sprinkler Efficiency / Distribution Uniformity
Sprinklers are unavoidably inefficient. Inefficiency of your system will likely range from 50%-80%, most well installed systems will be around 80%.
Enter the total square feet of irrigated area.
Enter your target inches per year for irrigation. For example, in my area the expected target is 40 inches per year, however I shoot for 30.
The information for this section is found on your water bill.
What type of units is the water billed in?
Enter the cost per unit found on your water bill.