Irrigation design and installation

Designing and Installing a Waterwise Irrigation System in Western Australia: A Practical Guide

With water scarcity an ongoing concern in Western Australia, particularly in the Perth metropolitan area and surrounding regions, designing and installing efficient irrigation systems is more critical than ever. The IAL Waterwise Standards, established by Irrigation Australia Limited in partnership with Water Corporation, provide a robust framework to help property owners, developers, and landscapers ensure their systems minimise water waste and promote sustainability.

This article explores the key considerations and steps involved in implementing a Waterwise irrigation system, with a spotlight on why Purely Irrigation is a trusted choice for compliant, high-performance irrigation solutions in Western Australia.

1. Why Waterwise Irrigation Matters in WA

Western Australia faces unique environmental challenges:

• A hot, dry Mediterranean climate

• Sandy soils with poor water retention

• Permanent water efficiency measures enforced by Water Corporation

• Increased pressure on urban water supplies

In response, the Waterwise Garden Irrigator Program was created to promote systems that deliver water efficiently to where it's needed most—at the plant root zone—without wastage from runoff, overspray, or evaporation.

Waterwise systems are not only a legal and environmental necessity but also a financial investment that reduces ongoing water bills and supports long-term landscape health.

2. Key Waterwise Principles (IAL Standards)

To be considered “Waterwise,” an irrigation system in WA must meet strict design and installation criteria, including:

• Hydrozoning: Grouping plants with similar watering needs

• Smart technology: Weather-based or soil moisture controllers

• Efficient distribution: Drip or low-flow sprinklers

• Seasonal adjustment: Scheduled watering based on climate conditions

• Leak detection and backflow prevention

• Use of approved irrigation components

As a Waterwise-accredited contractor, Purely Irrigation ensures every system meets or exceeds these standards—offering clients peace of mind and long-term savings.

3. Site Assessment: The Foundation of Effective Design

Every successful irrigation system begins with a comprehensive site assessment. This involves:

a. Soil Type and Drainage

Soils in Perth and regional WA range from hydrophobic sands to compacted clays. Sandy soils require:

• Shorter, more frequent watering cycles

• Pressure-compensating drip emitters

Clay-based soils benefit from slower precipitation rates to prevent runoff.

Purely Irrigation conducts soil testing and site-specific analysis to determine the correct irrigation techniques and emitter types.

b. Sun, Shade and Wind Exposure

These affect evapotranspiration rates. Shaded areas need less water; exposed areas may need wind-resistant emitters.

c. Water Pressure and Flow Rate

Static pressure and flow rate tests are essential. These determine the system’s zone configuration and the type of irrigation components required.

4. Sustainable Irrigation System Design

Designing a Waterwise system is a task for trained professionals. Purely Irrigation employs experienced, accredited designers who ensure:

a. Hydrozoning

Plants with similar water needs are grouped into zones. For example:

• Lawns (high water demand)

• Native gardens (low demand)

• Edible gardens or citrus trees (moderate demand)

Each zone has its own valve and schedule, minimising over-watering.

b. Irrigation Method Selection

• Drip irrigation is the preferred method for gardens and shrub beds due to its high efficiency.

• Micro sprays can be used in dense planting zones but must be controlled and low-pressure.

• Pop-up sprinklers for lawns should be fitted with matched precipitation rate nozzles and correct head spacing.

Purely Irrigation specialises in these configurations and only uses Waterwise-approved products, ensuring efficiency and durability.

c. Pressure Regulation and Filtration

Drip systems, in particular, require pressure regulation to prevent emitter blowouts, and filtration to prevent clogs.

d. Controller Integration

Smart irrigation controllers allow for:

• Seasonal adjustments

• Rain, freeze, and soil moisture sensors

• Wi-Fi or Bluetooth programming

Purely Irrigation offers full integration of these technologies, including user training.

5. Compliance with WA Regulations

Western Australian laws and Water Corporation regulations must be followed closely:

• Irrigation is restricted to certain watering days and times.

• Systems connected to mains water require a licensed plumber.

• Backflow prevention devices are legally required.

• Installations must comply with AS/NZS 3500 plumbing standards.

Using a licensed and Waterwise-accredited contractor like Purely Irrigation ensures full legal compliance and avoids costly retrofits or fines.

6. Installation Best Practices

Proper installation is critical to system performance and longevity. Key considerations include:

a. Trenching and Pipework

Pipes must be buried at appropriate depths and properly secured. Purely Irrigation uses high-quality PE and PVC pipe with UV-resistant fittings.

b. Valve Boxes and Solenoids

These must be easily accessible and labelled clearly. Waterproof wiring and proper valve placement reduce maintenance needs.

c. Emitter Placement

• Drippers must be placed at the plant’s dripline—not the base.

• Sprinkler heads must avoid overspray onto paths, driveways, or walls.

• Head-to-head coverage is necessary to prevent dry spots on lawns.

d. Controller Programming

Each zone is programmed according to plant type, soil, and exposure, aligned with Water Corporation’s watering day rules.

7. Commissioning and Testing

Post-installation, systems must be tested and commissioned. This involves:

• Flushing the system

• Pressure testing

• Zone-by-zone inspection

• Confirming sensor and controller function

• Adjusting nozzles and spray arcs

Purely Irrigation provides a detailed handover report, including diagrams, recommended maintenance, and a watering schedule.

8. Ongoing Maintenance and System Auditing

Even the best-designed system will fail without ongoing maintenance. Waterwise systems require:

a. Seasonal Adjustment

Controllers should be updated every 2–3 months to match temperature and rainfall trends.

b. Inspection of Emitters and Pipes

Check for leaks, blockages, or misalignment.

c. Cleaning Filters

Drip and micro systems must be flushed and filters cleaned regularly.

d. Professional Audits

Purely Irrigation offers scheduled system audits to measure distribution uniformity, efficiency, and compliance with IAL standards. This ensures long-term performance and identifies upgrade opportunities.

9. Integrating Rainwater and Greywater

For those seeking further sustainability:

a. Rainwater Tanks

Rainwater can be used for garden irrigation if connected to a pressurised pump system with appropriate filtration.

b. Greywater Systems

Water from laundry and bathrooms (excluding kitchen waste) can be reused for subsurface irrigation, subject to Department of Health WA regulations.

Purely Irrigation advises clients on these integrations and ensures all plumbing and environmental guidelines are followed.

10. Enhancing Water Efficiency Beyond Irrigation

Irrigation design is only part of the Waterwise equation. Landscape choices also affect water demand.

a. Native and Drought-Tolerant Plants

WA natives like grevilleas, kangaroo paws, and callistemons thrive with minimal water.

b. Mulching

Mulch helps retain soil moisture, regulate temperature, and reduce evaporation.

c. Lawn Alternatives

In low-use areas, consider artificial turf, native ground covers, or permeable paving.

Purely Irrigation works closely with landscape designers to create complete Waterwise outdoor environments.

11. Why Choose Purely Irrigation?

There are many irrigation contractors in WA, but few combine technical expertise, Waterwise accreditation, and customer-focused service the way Purely Irrigation does.

Here’s why they’re a smart choice:

• ✅ Waterwise Accredited: Recognised by Irrigation Australia and Water Corporation.

• ✅ Local Knowledge: Over 15 years of experience in Perth and regional WA.

• ✅ End-to-End Service: From design and installation to maintenance and audits.

• ✅ Smart Technology Specialists: Experts in smart controllers, soil moisture sensors, and water-saving tech.

• ✅ Compliance Guaranteed: Full adherence to WA plumbing and water regulations.

• ✅ Customer Satisfaction: Transparent pricing, clear communication, and reliable support.

Whether you’re a homeowner upgrading your garden, a developer planning a new estate, or a council upgrading parks and public spaces, Purely Irrigation brings unmatched value to every job.

Conclusion

Designing and installing a Waterwise irrigation system in Western Australia isn’t just about meeting regulations—it’s about building sustainable, intelligent landscapes that thrive in a dry climate.

From soil testing and hydrozoning to smart controller setup and backflow protection, every detail matters. Working with an experienced, Waterwise-accredited contractor like Purely Irrigation ensures your system is designed for the long-term—saving water, reducing costs, and supporting Western Australia’s commitment to sustainability.

If you're planning a new system or looking to upgrade an existing one, make the wise choice. Contact Purely Irrigation today and take the first step towards a greener, more water-efficient future.