Irrigation audit - measure it before you replace it
An audit puts numbers on how evenly your system actually waters. It is the cheapest way to find out whether you need a new system, a few adjustments, or just a better schedule.
What is irrigation audit?
An irrigation audit measures how much water each part of your landscape actually receives, rather than how much the controller says it applied. The core test is simple and physical: catch cans are laid out across a zone, the zone runs for a set time, and the volume in each can is compared. Wide variation between cans means the whole zone must be over-run to keep its driest spot alive - which is where most residential water waste comes from.
How irrigation audit actually works
Site walk-through and inventory
The auditor records what is actually installed: zone count, head types and nozzles per zone, controller model, sensors, and the plant material each zone serves. On older systems this frequently differs from any drawing that exists.
Watch forMixed head types found on one zone. It is extremely common on systems that have been repaired over many years, and it means that zone can never water evenly no matter what schedule you set.
Pressure readings at the heads
Pressure is measured at the nozzle, not at the valve - including at the furthest head on each zone. Pressure above design causes misting; below design causes short throw and dry gaps.
Watch forPressure taken only at the hose bib. That number tells you about your supply, not about what the last head on a long lateral is experiencing.
The catch-can test
Identical containers are placed in a grid across a zone, the zone runs, and the volume in each is measured. The results give both an application rate - how fast the zone applies water - and a uniformity figure describing how evenly it lands.
Watch forToo few cans, or cans placed only in the middle of the zone. Uniformity problems live at the edges and between heads; a grid that avoids those places produces a flattering and useless result.
Interpret uniformity against what it costs you
Poor uniformity has a specific financial consequence: to keep the driest area acceptable, the whole zone must run long enough for that spot, and everywhere else is overwatered by the difference. Improving uniformity reduces the run time the zone needs.
Watch forA uniformity number quoted without a recommendation attached. The figure is only useful if it comes with what to change and what that change would achieve.
Check soil and infiltration
How fast the soil can absorb water determines whether a zone should run once or in several shorter cycles. Clay and compacted soil accept water far more slowly than the rate most spray zones apply it, which produces runoff long before the root zone is wet.
Watch forA recommendation to increase run times on clay soil without cycle-and-soak. Longer single runs on slow soil produce more runoff, not more moisture.
Build a schedule from the measured numbers
With an application rate per zone and local seasonal demand, run times stop being guesses. Each zone gets a time derived from what it measurably applies and what its plants measurably need.
Watch forA schedule handed over as a single sheet with no explanation of how to change it later. You need to understand the logic, because next season's weather will not match this one's.
Prioritised recommendations, cheapest first
A good audit report is ordered by return: schedule changes first because they are free, then nozzle and arc corrections, then pressure regulation, then zone splits, then equipment. Replacement should be at the bottom, if it appears at all.
Watch forA report whose first recommendation is a new system from the company that wrote the report. That is a sales visit with catch cans.
What does irrigation audit cost?
An audit is usually a flat diagnostic fee scaled by zone count and property size - a fraction of what a system replacement costs. Some water utilities offer subsidised or free audits; it is worth asking yours. Full ranges in the Cost Guide.
See the full irrigation audit cost guide - by material, size and region →
If the number is the problem, here are the ways people pay for it →
HomeMatchup does not perform irrigation audit. We match you with licensed local irrigation pros for irrigation audit. Free for homeowners — Get matched free · how we verify pros.
When irrigation audit is the wrong call
When saying yes is the wrong move:
- Something is obviously broken. A zone that will not run, a geyser where a head used to be, a valve stuck open - fix those first. An audit measures a working system; auditing a broken one measures the breakage.
- You are replacing the system this year regardless. Auditing pipework that is about to be dug up is measurement for its own sake. Spend the money on getting the new design right instead.
- The auditor also sells the remedy and will not separate the two. The value of an audit is independence. If the same visit produces the diagnosis and the quote, ask whether they will do the audit as a standalone paid service with no obligation.
- You have two zones and a small lawn. On a very simple system you can lay out tuna cans yourself, run the zone, and see the variation with your own eyes. The formal report adds rigour that a small system does not need.
- You want it done in wind. Catch-can results in a breeze measure the wind, not the system. A serious auditor will reschedule rather than hand you data they know is unreliable.
- You expect it to reduce the bill on its own. The audit produces findings. The saving comes from implementing them, and some of the findings will cost money to act on.
Types of irrigation audit
| Option | What it means for you |
|---|---|
| Water conservation upgrades | What audits most often recommend: pressure regulation, matched-rate nozzles, and drip conversion for beds. |
| Local watering restrictions | Restrictions change what an efficient schedule even looks like - check your utility's current stage. |
| Smart Irrigation Installation | The upgrade an audit most often justifies - and occasionally rules out. |
| Irrigation System Redesign | Where the audit finds the zoning itself is the constraint. |
What to check when hiring for irrigation audit
- Are you a Certified Landscape Irrigation Auditor? The Irrigation Association runs a Certified Landscape Irrigation Auditor (CLIA) programme specifically for this work. Auditing is not licensed anywhere in the way plumbing is, so a voluntary credential is a genuine signal rather than a formality.
- Do you run a catch-can test, and on how many zones? Without measurement it is an inspection, not an audit. Ask whether every zone is tested or a representative sample, and how the sample was chosen.
- Will I get the raw measurements, not just conclusions? Catch-can volumes, pressure readings and application rates are your data. They let you get a second opinion and let you re-check after changes.
- Are your recommendations ordered by cost and by expected effect? This is what separates a diagnostic report from a quotation. You should be able to do the free things first and measure whether they worked.
- Do you sell the work you recommend? Not disqualifying, but you should know. If they do, ask whether you can take the report elsewhere without penalty.
- Will you set the controller schedule from the measured application rates? The schedule is where the audit turns into a saving, and it is often the only recommendation that costs nothing to implement.
- Does my water utility subsidise this? Some utilities fund landscape water audits or offer them directly. Worth a phone call before paying full price - but confirm it with the utility, not with the contractor.
Irrigation Audit near you
Local pro matching for irrigation audit is rolling out by metro. Enter your ZIP and we'll match you with local pros in your area today.
Sources
Sources last checked
- WaterSense — Outdoor Water UseU.S. Environmental Protection AgencyRetrieved 2026-08-04Federal efficiency labeling and outdoor water-use guidance.
- Occupational Employment and Wages — Construction TradesU.S. Bureau of Labor StatisticsRetrieved 2026-08-04Labor cost context for home-services trades nationally.
Sources for figures and claims on this page.
Get irrigation audit quotes
Matched irrigation pros. Free for homeowners.
Free · No obligation