The Water Neutral Pool program

SPASA Victoria

Friday, 10 May, 2019

The Water Neutral Pool program

The Swimming Pool & Spa Association of Victoria's (SPASA Victoria) 'Water Neutral Pool program' is a benchmark in energy efficiency and water sustainability. Supported by the greater metropolitan water retailers, a Water Neutral Pool is one that creates a new standard for swimming pools utilising both water-saving and water-harvesting devices to ensure that it is 'water-wise' by minimising mains water use.

A Water Neutral Pool delivers a range of benefits including:

  • Reduced water use — delivering water savings, energy savings and cost savings while reducing the impost on mains water.
  • Reduced chemical use — cuts pool maintenance costs.
  • Water collection at site — another way of saving water and money by storing water and diverting it for use in laundries and toilets, and on gardens.
  • Enhanced property value.
  • Demonstration of the pool owner's responsible attitude to water conservation.

The Water Neutral Pool program has been designed using Bureau of Meteorology rainfall figures and evaporation rates to assess the effectiveness of a range of water-saving devices and techniques.

A Water Neutral Pool must, at a minimum, have the following features:

  • Water tank, to collect rainfall to top up the pool as needed.
  • Pool cover, to conserve 90% of water lost through evaporation.
  • Backwash minimisation system, to prevent excessive backwashing (eg, cartridge filter, oversized sand filter, centrifugal/pre-filter device, backwash recycle system etc).
  • Energy-efficient equipment.

There are a range of other positive options that pool owners can take to maintain a water-wise pool, including:

  • Installing shade sails and wind covers to help prevent evaporation.
  • Ensure the pool has suitable overhanging pavers or decking to keep splash-out to a minimum.
  • Never over-fill a pool.
  • Keeping your pool's water in the correct condition or 'balanced' to avoid emptying polluted water.
  • Check pipes and drains each year to ensure there are no leaks.
  • Keeping pets out of the pool.
  • Discouraging rough play and unnecessary splashing by pool users.

Analysis shows a Water Neutral Pool can save thousands of litres of water every year. Over a 12-month period, pool owners with an adequate-sized rain tank, who conscientiously use a pool blanket (physical or chemical) and a backwash minimisation system, will not need to use mains water to top up their pool.

This has been tested using two scenarios — average rainfall in Melbourne over a 30-year period (1971–2000) and average rainfall in the past 10 years (1997–2007) — that have been affected by climate change and drought.

The results show for both examples there is excess water in the rainwater tank that can be used for other purposes around the home over the 12-month period.

The table below shows how much water can be saved annually by implementing a Water Neutral Pool. The data is based on an 8 x 3.5 metre, 40,000-litre capacity pool (calculations are based on use of pool cover 50% of the time) and compares:

A. A non-Water Neutral Pool.

B. A Water Neutral Pool over a 30-year period (1971–2000) based on average rainfall and evaporation rates.

C. A Water Neutral Pool over a 10-year period (1997–2007) based on average rainfall and evaporation rates during this time of drought and climate change.

  Rainfall into pool Rainfall into water tank Loss to water tank diverter Water gained  Loss through evaporation Backwash loss Total water loss Surplus water
A 18,329 N/A N/A N/A 34,124 5724 39,848 -21,519
B 18,329 32,730 8700 42,359 17,062 2862 19,924 22,435
C 12,555 22,420 8700 26,275 17,062 2862 19,924 6351

The data shows:

  • Even during a time of drought, a Water Neutral Pool provides 6351 surplus litres of water that can be used by the pool owner in their garden, laundry or toilet.
  • The importance simple devices such as water tanks and pool covers can play.
  • A mix of devices produces the best water conservation outcomes.
  • Having a Water Neutral Pool is easy and achievable and delivers real water savings benefiting the whole community.

To calculate water collection capacity, Bureau of Meteorology average rainfall data was used to determine the amount of water a pool could capture as well as how much run-off a 50 m2 roof would send to a water tank.

To calculate water loss, Bureau of Meteorology evaporation rates based on a pool’s surface area, backwash loss from the filter and the diverter were used. The diverter is connected to the water tank and stops pollutants from the catchment area entering the tank, losing some water in the process.

The experience of SPASA Victoria members was used to determine the amount of water used in an average swimming pool.

SPASA Victoria is keen to be a leader and promote good water management practices as well as to educate consumers on how they can own a pool as well as make real, positive contributions towards water efficiency.

SPASA Victoria is proud of its Water Neutral Pool program and is pleased to work with industry and consumers who are keen to play their part and promote sensible water use and water-wise behaviours.

Credit: ©

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