Product Overview

Summary: This SOP sets out a clear, step-by-step approach to managing water treatment in HVAC and refrigeration systems to control corrosion, scale, microbiological growth and Legionella risk. It supports compliance with Australian WHS and public health requirements while improving plant reliability, energy efficiency and asset life.

Poorly managed water treatment in HVAC and refrigeration systems can lead to serious safety, health and operational issues – from Legionella outbreaks and chemical exposure to equipment failure, unplanned downtime and excessive energy use. This Safe Operating Procedure provides a structured, defensible method for assessing, dosing, monitoring and maintaining water quality in cooling towers, evaporative condensers, chilled water loops and associated plant. It is written specifically for Australian workplaces and aligns with current WHS duties, public health expectations and industry best practice.

The SOP walks your team through each stage of the water treatment lifecycle: from system commissioning and baseline testing, through routine inspections, dosing and recordkeeping, to corrective actions when results fall outside specification. It clearly defines roles and responsibilities between building owners, facility managers and external water treatment providers, minimising confusion and gaps in control. By implementing this procedure, businesses can demonstrate due diligence in managing Legionella and other microbiological risks, extend the life of critical HVAC and refrigeration assets, and provide consistent training material for technicians and contractors operating across multiple sites.

Key Benefits

• Ensure systematic control of Legionella and other microbiological risks in HVAC and refrigeration water systems.
• Reduce corrosion, scaling and fouling to extend equipment life and maintain energy-efficient operation.
• Demonstrate due diligence and compliance with Australian WHS and public health obligations for cooling water systems.
• Standardise water treatment tasks, testing frequencies and documentation across all sites and contractors.
• Improve incident readiness with clear escalation pathways when test results or inspections identify non-conformances.

Who is this for?

• Facility Managers
• HVAC Technicians
• Refrigeration Mechanics
• Building Services Engineers
• WHS Managers
• Maintenance Supervisors
• Property and Asset Managers
• Water Treatment Contractors
• Risk and Compliance Managers

Hazards Addressed

• Legionella bacteria growth in cooling towers and evaporative condensers
• Exposure to hazardous water treatment chemicals (corrosives, oxidising biocides, acids and alkalis)
• Aerosol inhalation from contaminated drift or mist around cooling systems
• Corrosion-related equipment failure leading to leaks, structural damage or system collapse
• Scale and biofilm formation causing overheating, reduced heat transfer and potential plant damage
• Confined space and access risks when inspecting or cleaning cooling towers and plant rooms
• Slips, trips and falls around wet surfaces and water treatment plant
• Manual handling injuries from lifting chemical drums and equipment

Included Sections

• 1.0 Purpose and Scope
• 2.0 Definitions and System Types (Cooling Towers, Chilled Water, Condenser Water, Evaporative Systems)
• 3.0 Roles and Responsibilities (Owner, Facility Manager, Water Treatment Provider, Technicians)
• 4.0 Applicable Legislation, Standards and Guidance
• 5.0 System Description and Critical Control Points
• 6.0 Required PPE, Safety Controls and Chemical Handling Requirements
• 7.0 Pre-Start Checks and Baseline Water Quality Assessment
• 8.0 Routine Water Treatment Procedures (Dosing, Bleed-Off, Biocide and Corrosion Control)
• 9.0 Water Sampling, Testing Schedules and Acceptance Criteria
• 10.0 Legionella and Microbiological Control Measures
• 11.0 Inspection, Cleaning and Disinfection of Cooling Towers and Associated Plant
• 12.0 Managing Abnormal Results, Non-Conformances and System Alarms
• 13.0 Shutdown, Start-Up and Seasonal Commissioning Procedures
• 14.0 Chemical Storage, Transport, Spill Response and Waste Disposal
• 15.0 Recordkeeping, Logbooks and Reporting Requirements
• 16.0 Training, Competency and Contractor Management
• 17.0 Review, Audit and Continuous Improvement of Water Treatment Program

Legislation & References

• AS/NZS 3666.1: Air-handling and water systems of buildings – Microbial control – Design, installation and commissioning
• AS/NZS 3666.2: Air-handling and water systems of buildings – Microbial control – Operation and maintenance
• AS/NZS 3666.3: Air-handling and water systems of buildings – Microbial control – Performance-based maintenance of cooling water systems
• AS/NZS 3666.4: Air-handling and water systems of buildings – Microbial control – Performance-based maintenance of air-handling systems (ducts and components)
• AS 4032 series: Water supply – Valves for the control of heated water supply temperatures
• Work Health and Safety Act and Regulations (as implemented in each Australian state and territory)
• Safe Work Australia – Managing Risks of Hazardous Chemicals in the Workplace Code of Practice
• Safe Work Australia – Managing the Work Environment and Facilities Code of Practice
• Relevant state and territory public health regulations for cooling towers and warm water systems (e.g. NSW Public Health Regulation, Victoria Public Health and Wellbeing Regulations)