Irrigation System Efficiency Audit in Glendale, Arizona

An irrigation audit in Glendale measures what each zone really does, under the conditions it really runs in. In this city those conditions include a pressure system that changes by the hour, soil that resists deep watering, and a rebate program that rewards some upgrades but only after the system works.

Measure at the right hour

The City of Glendale says it has four pressure zones and that pressure may drop from 6 to 8 a.m. and from 6 to 9 p.m. An audit run at midday can make a dawn-scheduled system look better than it is. Catch-can tests on turf, and timed checks at drip emitters, should run at the hour the controller normally runs each zone. Where a zone is weak only in the peak window, moving its start time can be the cheapest fix in the report.

Reading the results on Glendale soil

Catch cans show how evenly a lawn is watered and how fast. Glendale's caliche, which University of Arizona Cooperative Extension says stops water from penetrating deeper, means that fast application can run off before it soaks in. A soil probe after the cycle shows how deep the water went. If the top few inches are wet and the root zone is dry, the fix is usually shorter cycles repeated with a soak in between, not more minutes. For drip, the audit checks each plant group, because a tree that has outgrown its emitters will show stress no schedule can fix.

What the audit should produce

A written report with:

• every station, what it waters, and how it performed at its scheduled hour;
• faults found, separated into repairs that stop waste and optional upgrades;
• a starting schedule for each season, based on the measurements, with start times that avoid the morning pressure dip;
• notes on runoff, since the city's drought plan treats runoff that travels 250 feet or pools over 200 square feet as water waste.

Before booking an audit

Gather two or three recent water bills, the controller program and a sketch of which station waters what. Note every area that stays wet or dry. If the bill jumped while the schedule did not change, run the meter test on the leak detection page first, because a leak distorts every other measurement. On a downtown lot that takes urban flood irrigation, give the delivery dates so flood water is not mistaken for sprinkler output.

Where the city fits in

The City of Glendale offers its water customers a free landscape consultation, links to the AMWUA water use calculator, and rebates on smart controllers, high-efficiency nozzles, WaterSense spray bodies, rain sensors and flow sensors for single-family homes. Every rebate requires an irrigation system in good working order, so the repairs in the audit come first and the upgrades second. Check the city's current rebate terms before buying, since products and limits change between fiscal years.

The audit service page explains the method. Use the inspection checklist between audits, and the rebate guide for the upgrade list. If the audit finds leaks, see leak detection in Glendale.