The use of filtered clean rainwater collected from the roof (not general stormwater runoff) to fill spa pools and swimming pools is supported provided controls are in place to protect public health. Rainwater collected in tanks can be safely used for pools provided it is introduced into the pool through either the balance tank or into the pool at night to allow sufficient time for treatment before bathers enter the pool.

Last updated: 24 April 2013

Overview

The use of filtered clean rainwater collected from the roof (not general stormwater runoff) to fill spa pools and swimming pools is supported provided controls are in place to protect public health. Rainwater collected in tanks can be safely used for pools provided it is introduced into the pool through either the balance tank or into the pool at night to allow sufficient time for treatment before bathers enter the pool.
 
Safe rainwater use for swimming pools is achievable in most situations, unless rainwater is collected from roofs either constructed of hazardous materials (such as lead or preservative-treated timber) or located in heavily polluted areas where particulate pollution from vehicles, aircraft and industrial activities may contaminate rainwater.
 
Research indicates that first flush systems effectively minimise particulate and microbial pollution. First flush systems reduce contamination because the first few litres of rainwater, which contain the highest concentration of pollutants, are discarded to stormwater. Microbial contamination of rainwater can also be easily controlled by chlorination in the collection tank. The area of the roof needs to be considered when determining the quantity of first flush water to discard. The rainwater tank must be maintained and checked periodically for sludge accumulation.
 
Rainwater can have the added benefits of a low Total Dissolved Solids and is therefore soft water being low in carbonates. In heavily polluted areas, the cost of pre-treatment to maintain safe water may outweigh any benefits, especially where a reliable water source exists. Further information is contained in Rainwater Tanks (2) and Guidance on use of rainwater tanks.(3)
 
The use of filtered clean rainwater to top-up swimming pools is supported provided controls are in place to protect public health. A suggested risk assessment and management framework is outlined below.

Components to consider in water harvesting for use in swimming pools

(Developed for use with Australian Guidelines for Water Recycling: Managing Health and Environmental Risk (Phase 1), 2006(1)
Framework element Activity
Element 1:
Commitment to responsible use and management of rainwater to top-up swimming pools
 
 
Components:
Rainwater use policy
 
Regulatory and formal requirements
 
Engaging stakeholders
 
Regulatory framework - compliance

Water Quality Guidelines:
  • NSW Health. Public Swimming Pool and Spa Pool Guidelines(4)
Heath risk assessment guidelines:
  • Australian Guidelines for Water Recycling: Managing Health and Environmental Risk (Phase 1), 2006(1)
  • EnHealth. Guidance on use of rainwater tanks. May 2004(3)
Develop a rainwater use policy
Element 2:
Assessment of the water system
 
Components:
Identify intended uses
 
Component:
Hazard identification and risk assessment​
Source of water
  • Rainwater tank
 
Treatment
  • First flush system
  • UFF filtration or other pre-treatment
  • Disinfection: ultraviolet (UV)
  • Introduced into the pool plant and not directly into the pool
 
Intended uses
  • Recreational swimming
 
Exposure routes
  • Ingestion (100 mL) - more for infants
  • Dermal: disinfection by-product (DBP) - trihalomethanes (THM)
  • Inhalation: DBP - THM
 
Assessment of water quality data
  • Microbial quality
  • Chemical quality (heavy metals), pH, total dissolved solids (TDS), turbidity
 
Water Quality Indicators
  • Turbidity (NTU), TDS
  • Oils and grease
  • Salts (coastal locations)
  • Heavy metals (lead, copper)
  • Microbiological indicators
 
Rainwater to be validated prior to use
  • Microbial hazards
  • Chemical hazards
  • Hazards from failures
Element 3:
Preventive measures for recycled water management
 
Components:
Preventive measures and multiple barriers
 
Critical control points
 
Preventative Measures
  • Prevention - roofing materials, flashing (not lead)
  • Treatment -best available technology (first flush system)
  • Validation of treatment system
  • Documentation of responsibilities, operational procedures
  • Controls - monitoring, shutdown
 
Multiple barriers/prevention/communication
  • Rainwater water should be tested prior to use.
  • Failures should be communicated and reported to the Public Health Unit (PHU)
  • A contingency plan should be developed to effectively deal with rainwater contamination events.
  • Education program for operational staff
  • Validation prior to commissioning to ensure that rainwater complies with the Australian Drinking Water Guidelines in relation to e.g. turbidity, TDS, oils and grease, heavy metals, and microbial indicators.
  • On-line monitoring of pool water for TDS, turbidity, free chlorine and oxidation-reduction potential (ORP) (may be required)
  • Determine critical control points
Element 4:
Operational procedures and process control
Documented procedures
  • Operational monitoring
  • Develop a contingency plan for contamination events
  • Corrective advice​
Element 5:
Verification of rainwater quality
  • Water quality monitoring
  • Receiving water monitoring
  • Documentation and reliability
  • User satisfaction
  • Short-term evaluation of results
  • Corrective action​
Element 6:
Management of incidents and emergencies
  • Communication
  • Incident and emergency response protocol
Element 7:
Equipment capability and maintenance
  • Operator, contractor and end user awareness and training​
Element 8:
Community involvement and awareness
  • Community consultation and education​
Element 9:
Validation, research and development
  • Validation of processes
  • Design of equipment
  • Investigative studies and research monitoring​
Element 10: Documentation and reporting
  • Management of documentation and records
  • Reporting
Element 11: Evaluation and Audit
  • Long term evaluation of results
  • Audit of rainwater - water quality management​
Element 12: 
Review and continual improvement
  • Review by senior management
  • Continual improvement
 
 

Reference

  1. National Resource Management Ministerial Council; Environment Protection and Heritage Council; Australian Health Ministers Conference. National Water Quality Management Strategy. Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1). 2006. Available at: http://www.environment.gov.au/resource/national-water-quality-management-strategy-australian-guidelines-water-recycling-managing-0 (Cited 28 April 2009)
  2. NSW Department of Health. Rainwater tanks. Sydney: NSW Health, 2007. Available here (Cited 28 April 2009). 
  3. Australian Government Department of Health and Ageing, enHealth Council. Guidance on use of rainwater tanks. 2nd edition. Canberra, 2004. Available at: http://www.nphp.gov.au/enhealth/council/pubs/documents/rainwater_tanks.pdf(Cited 28 April 2009)
  4. NSW Department of Health. Public Swimming Pool and Spa Pool Guidelines. Sydney: NSW Health, June 1996, the NSW Health swimming pool website

Further Information

In NSW call 1300 066 055 to talk to your local Public Health Unit​