How to Fill Out and Submit an Irrigation Audit Form

To fill out an irrigation audit form, work through it in the order the fieldwork happens: identify the project and water supply at the top, log the controller and its stations, run a catch-can test on each zone, calculate distribution uniformity and precipitation rate from the catch data, enter hydrozone and plant details for every area, and finish with a recommended irrigation schedule built from those numbers. The sections below walk through each field, where the data comes from, and what a complete entry looks like.

What the Form Covers

A standard audit form documents how efficiently your sprinkler or drip system delivers water. It records the hardware, measures how evenly water lands across each zone, and produces an irrigation schedule tailored to the actual conditions on site.¹ The most widely used templates come from the California Department of Water Resources (DWR), the Irrigation Association, and the QWEL program, and local jurisdictions borrow from them, so the fields on your form will track closely with the ones described here.

Project and Water Supply Fields

The top of the form captures identification: project name, address, inspection date, and the auditor’s name, company, and contact information. If a certified auditor is signing, their certification program goes here too.²

Next comes the water supply. Record the meter type (customer service meter or submeter) and the meter size in inches. The meter size is a dimension, not the model number, which is a common mix-up.³ For static water pressure, attach a pressure gauge to a hose bib while the system is off and take the reading at the same time of day you normally irrigate, because municipal pressure fluctuates. Enter the value in PSI. A reading below 25 PSI or above 125 PSI is worth investigating with your utility before you continue.⁴

The point-of-connection section asks you to confirm and describe the safety and control hardware. Identify the backflow prevention device by type (reduced-pressure assembly, atmospheric vacuum breaker, anti-siphon valve, or double-check valve assembly). Confirm a manual shutoff valve and note its location. Indicate whether a master valve is installed and whether it is connected. Note the presence and location of a flow sensor, which larger landscapes often require. Record whether a pressure-reducing valve is in place.²

Controller and Station Entries

In the controller section, enter the manufacturer, model number, and location. Mark whether it is a conventional timer or a smart controller (weather-based, soil-moisture-based, or both). For smart controllers, indicate whether the controller pulls data from an on-site weather station or a regional data network.⁵ If the unit carries the EPA WaterSense label, note that where the form provides a field for it; the label means the controller has been independently certified against federal efficiency criteria.⁶

For every station on the controller, log the program assignment, run time, start times, irrigation interval, and any rain-delay or percent-adjust settings. On a smart controller, you also enter the precipitation rate, distribution uniformity, plant factor, soil type, slope, and soil-moisture reading the controller uses to auto-adjust.⁵

Running the Catch-Can Test

The catch-can test produces the data that drives the two most important numbers on the form: distribution uniformity and precipitation rate. Before you set up any cans, walk the system while it runs and look for broken heads, clogged nozzles, tilted risers, overspray onto hardscapes, and leaks. Fix problems first. Running the test on a broken system gives you bad data.

Sketch a map of the test area showing every head, its type, and the spacing between heads. Place at least 24 identical flat-bottomed catch cans or commercial catch cups in a grid. Spacing depends on the sprinkler type:

Fixed spray heads in an irregular layout: 5 to 8 feet apart.
Fixed spray heads in rows: 10 to 20 feet apart.
Rotor sprinklers in an irregular layout: 10 to 20 feet apart.
Rotor sprinklers in rows less than 40 feet apart: one can 2 to 3 feet from the head, then every one-third of the distance to the next head.
Rotor sprinklers in rows more than 40 feet apart: one can 2 to 3 feet from the head, then every one-fourth of the distance to the next head.

Keep every can 12 to 24 inches inside the irrigated area so you don’t capture runoff from adjacent surfaces. Choose a calm day, because wind above 5 mph distorts the results. Run the zone for a measured amount of time and write that time down exactly. After the run, measure the volume collected in each can in milliliters and record every reading on the data sheet.

Calculating Distribution Uniformity and Precipitation Rate

Distribution uniformity (DU) tells you how evenly water lands. Use the lower-quarter method (DU-LQ): sort all catch-can readings from smallest to largest, average the lowest 25 percent, then divide that average by the overall average of all cans.⁷ The result is a decimal between 0 and 1.0, or a percentage if you multiply by 100. A perfect system scores 1.0; most real-world spray systems fall around 0.5 to 0.7, and well-maintained rotors reach 0.7 or higher. Enter the DU value in the distribution uniformity test section for the zone.

The DWR checklist also asks for irrigation efficiency (IE), which is DU multiplied by a water-management percentage reflecting how well the schedule matches plant water demand.²

Precipitation rate (PR) is how much water the system applies per hour, in inches per hour. The Irrigation Association’s formula is:

PR = (3.66 × V) ÷ (t × A)

V is the average catch volume in milliliters, t is the test run time in minutes, and A is the throat area of the catch device in square inches.⁸ Record this number in the hydrozone row for the zone, next to the zone’s flow rate in gallons per minute.

Hydrozone and Plant Data

Each zone gets its own row of physical characteristics. The standard fields on the DWR checklist and Irrigation Association worksheets are:

Irrigated area in square feet.
Plant type: turf, high water use, medium water use, low water use, or very low water use.
Sun exposure: full sun, mostly sun, partial sun, partial shade, full shade, or mostly shade.
Slope: none, gentle, or steep.
Soil type: clay, clay/loam, loam, sandy/loam, or sandy.
Irrigation method: drip, spray, rotating nozzles, rotor, bubbler, or microspray.
Zone pressure readings taken at the beginning, middle, and end of the zone.
Water type: potable, recycled, graywater, or stormwater.²

Plant type feeds the water budget calculation. Under the EPA WaterSense water budget approach, high water-use species consume 70 to 90 percent of reference evapotranspiration (ETo), moderate species use 40 to 60 percent, and low water-use species need less than 30 percent.⁹ If you have the original landscape plan, confirm species and water-use categories against it instead of guessing in the field.

If your form uses the Irrigation Association’s expanded worksheets, there are additional site-conditions fields: root zone depth, whether compaction exists, runtime until runoff occurs, standing water, mowing height, fertilization and aeration frequency, and whether mulch is in the beds. The equipment review worksheet also gives you a checklist for broken pipes, missing heads, clogged nozzles, arc misalignment, low-head drainage, leaking seals, mismatched heads, and uneven spacing, so you can document every deficiency on site.⁵

Building the Recommended Irrigation Schedule

The last substantive section of the form is a recommended schedule built from the data you just collected. For each station, enter the target amount of water to apply (based on plant water requirements), the precipitation rate, the DU, and a scheduling multiplier that accounts for non-uniform application. The Irrigation Association worksheet then calculates an ideal run time and an upper boundary, and you choose a recommended run time within that range.⁵ If the run time exceeds what the soil can absorb before runoff starts, split it into shorter cycles with soak-in periods between them.

The QWEL form takes the same approach, calculating plant water requirement as reference ETo multiplied by the plant factor, then using the net precipitation rate and DU to determine how many minutes each zone needs.³

When You Can’t Sign the Form Yourself

Many jurisdictions require a certified irrigation professional, not the property owner, to perform and sign the audit. Thresholds vary. Some ordinances apply the requirement to all non-residential properties; others trigger it when the irrigated area exceeds a set square footage. Check with your local water agency or building department before you start, because an owner-completed form may not be accepted for your project.

The most widely recognized credential is the Certified Landscape Irrigation Auditor (CLIA) designation from the Irrigation Association.¹⁰¹¹²

Submitting the Completed Form

Where you send the finished audit depends on your jurisdiction and the reason the audit was required. For new construction and rehabilitated landscape projects, the audit report is typically submitted with a certificate of completion package to the local agency that approved the landscape plans. Some water utilities take the form separately through an online portal or by mail to their conservation department.

Before you submit, work through the final summary table on the checklist and confirm each step is complete: system inspection, leak inspection, tune-up, operating pressure test, distribution uniformity test, precipitation rate test, matched precipitation rate confirmation, overspray and broken equipment report, runoff report, written recommendations, and irrigation schedule preparation.² Incomplete forms are the most common reason for delays, so make sure every applicable box is checked and every data field has a value.

Keep a copy of the completed form, every catch-can data sheet, the recommended irrigation schedule, and any photographs of equipment deficiencies. If your jurisdiction later conducts a site verification or asks for documentation during a water-use review, you’ll have the full file ready instead of reconstructing data from memory.

1
California Department of Water Resources. Looking for a Certified Irrigation Auditor
2
California Department of Water Resources. Landscape Irrigation Audit Form
3
QWEL. Landscape Irrigation Audit Form
4
Oklahoma State University Extension. Managing Pressure in the Home Irrigation System
5
Irrigation Association. Landscape Irrigation Auditor Blank Worksheets
6
US EPA. WaterSense Labeled Controllers
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Irrigation Association. Evaluation of Uniformity Measurements From Landscape Irrigation Auditing
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Irrigation Association. Recommended Audit Guidelines
9
US EPA. WaterSense Water Budget Approach
10
My Next Move. Certified Landscape Irrigation Auditor
11
US EPA. Professional Certification