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.
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.
(Developed for use with Australian Guidelines for Water Recycling: Managing Health and Environmental Risk (Phase 1), 2006(1)
Water quality monitoring (turbidity, TDS, DBP, microbial)
In NSW call 1300 066 055 to talk to your local Public Health Unit.