What Is an Irrigation Audit and Why Does It Matter?
- Briana Johnson
- May 7
- 4 min read
California landscapes face mounting pressure from persistent drought conditions, escalating water costs, and increasingly strict regulatory requirements. In this environment, irrigation systems that once functioned adequately can quickly become liabilities—leading to wasted water, noncompliance, and landscape decline.
An irrigation audit offers a proactive solution.
Table of Contents
Understanding Irrigation Audits
An irrigation audit is a comprehensive, data-driven evaluation of your landscape irrigation system. The objective is to assess the system’s efficiency, identify performance issues, and generate recommendations that support both water conservation and landscape vitality.
This process is more than a surface-level inspection. A certified irrigation technician evaluates system hardware, water distribution patterns, and controller programming, ensuring the system aligns with California’s Model Water Efficient Landscape Ordinance (MWELO) and local conservation mandates.
What’s Included in a California Irrigation Audit?
A California irrigation audit is not a simple walkthrough. It is a systematic, performance-based evaluation conducted by certified professionals to assess the efficiency, functionality, and compliance of an existing irrigation system. The process includes the following key components:
1. Visual Inspection of All System Components
Every component of the irrigation system is visually reviewed to assess condition and functionality, including:
Lateral and main lines (checked for visible leaks and pressure issues)
Valves (manual and automatic)
Emitters, drip lines, micro-sprays, rotors, and fixed spray heads
Backflow prevention devices and filters
Controllers and sensors (rain, soil moisture, wind)
Master valve and flow sensor integration (if applicable)
During this phase, the auditor documents any signs of wear, damage, clogging, misalignment, or incompatibility that could compromise performance or water use efficiency.
2. Water Pressure and Flow Testing
Water pressure is tested at multiple points within the system to confirm that it falls within the manufacturer’s recommended operating range. Excessively high or low pressure can lead to:
Misting and evaporation losses
Uneven coverage and overwatering/underwatering
Premature equipment failure
Flow rate is also measured to establish a baseline for each hydrozone. This information is used to calculate precipitation rates and match irrigation output to plant water needs and soil infiltration capacity.
3. Coverage and Distribution Uniformity Analysis
This is a critical phase of the audit, especially for properties using overhead spray or rotor systems. Auditors place catch cans (or similar measurement tools) throughout the irrigation zones and run the system to:
Measure the amount of water applied across different areas
Identify overspray, gaps, and excessive overlap
Calculate Distribution Uniformity (DU), a key performance metric
A low DU score indicates that some areas are receiving more water than others, leading to waste and plant stress. Corrective recommendations might include adjusting heads, changing nozzles, or retrofitting zones.
4. Controller Programming and Scheduling Review
A thorough review of controller settings includes:
Verification of run times, cycle/soak programming, and frequency
Matching irrigation schedules to plant material, microclimate, and soil type
Checking seasonal adjustments and weather-based automation features
Ensuring alignment with MWELO requirements and local drought restrictions
Controllers are often programmed improperly or left on outdated seasonal settings. Adjustments here can result in immediate and measurable savings.
5. Soil and Site Evaluation
The auditor reviews each irrigation zone in terms of:
Soil type and infiltration rate (to avoid runoff)
Plant type and water demand
Slope, compaction, and shade vs. sun exposure
Drainage challenges and ponding risk
Understanding the physical and horticultural context of each hydrozone ensures irrigation schedules and equipment choices are appropriate. For example, drip irrigation might be recommended for densely planted areas with clay soils to allow for slower absorption and minimal runoff.
6. Runoff and Overspray Analysis
Irrigation runoff not only wastes water but can lead to fines in jurisdictions with water discharge restrictions. Auditors assess whether water is:
Flowing onto hardscapes, streets, or neighboring properties
Ponding in unintended areas
Failing to be absorbed due to excessive application rates
Corrections may involve equipment upgrades, schedule adjustments, pressure regulation, or retrofitting zones with more appropriate distribution methods.
7. Performance Reporting and Compliance Documentation
The final audit report includes:
A zone-by-zone summary of findings
Photographs and data charts for reference
Recommended improvements, prioritized by impact
Documentation to support MWELO compliance
Data that may qualify the property for water agency rebates or incentive programs
Why an Irrigation Audit Matters
The value of an irrigation audit becomes clear when viewed through three lenses: resource conservation, regulatory compliance, and long-term asset protection.
Water conservation: California’s climate demands efficient irrigation practices. An audit identifies opportunities to reduce waste, often leading to measurable reductions in water use.
Cost control: Correcting inefficiencies can significantly lower utility costs and help clients avoid noncompliance penalties.
Regulatory alignment: Many California municipalities require irrigation audits for properties above a certain size or as part of development and renovation projects.
Landscape health: Over- or under-watering can weaken plant health, increase susceptibility to pests and disease, and shorten the lifespan of expensive landscape elements.
Audits provide a foundation for achieving landscape sustainability—balancing plant needs with environmental stewardship.
Schedule Your Irrigation Audit
An irrigation audit is a wise investment. It protects your landscape, conserves water, and can help you save on utility bills. This assessment also keeps you in compliance with California’s evolving water ordinances.
At Gardenworks Inc., our team includes certified irrigation specialists who understand the unique needs of Sonoma County landscapes. We’re deeply familiar with California’s water policies and conservation goals, helping clients meet all local water-use requirements.
Call Gardenworks Inc. today at (707) 857-2050 to schedule your irrigation audit.
