Residential Pools and Spas

Cleaning and maintaining swimming pools after fires and floods

February 13, 2019

Following the devastating bushfires and floods that have ravaged parts of Australia, pool and spa specialist network Swimart has provided some key information to enable pool owners to help restore healthy water balance.


Many swimming pools in affected areas and beyond may be experiencing a build-up of ash and debris, greatly impacting the quality of the water.

“After bushfires swimming pools can become contaminated by impurities such as embers, ash and other debris – and this can significantly impact the chemical balance,” says Swimart’s Rick Graham. “The result will be dirty, green or cloudy pool water.”

There are several crucial steps pool owners can take to clean and maintain the pool and ensure it can be safely used again:
• To start with, it is important to remove as much debris and ash from the pool and ensure the skimmer and pump baskets are clean;
• Remove as much debris as possible from the surface of the water with a leaf rake;
• Turn the pool pump on to skim any remaining ash and leaves from the surface of the water;
• Take a water sample to your local store to be assessed and they will advise what’s required to safely rebalance your pool water and ensure it’s fine for swimming;
• The service technician will also advise whether the pool requires flocculant;
• If the ash and dirt is substantial, use a liquid or granular flocculant to make the debris and organic matter drop to the floor;
• Clean your filtration. For cartridge filters, remove the cartridge and hose it down. For sand and media filters, backwash and rinse the filter;
• If staining has occurred, see your local retailer for the appropriate solution.

“If any circuits or electrical fittings of your pump, timer or electrical equipment have been damaged by fire, it’s important to get an electrician to first check the electrical outlets are still in good working order,” says Graham.

“Then get your local pool technician to thoroughly check your swimming pool equipment. If needs be, they can prepare a report and quote for your insurance company.

“We also advise pool owners not to empty their pools without first checking with an expert due to the risk of serious damage. The fact is that all swimming pools – whether they’re vinyl-lined, fibreglass or even concrete ones weighing over 50 tonnes – can float when empty. The upward pressure of the water under the floor can actually cause it to lift.”


Thousands of people have been affected by the devastating floods and heavy rains across Queensland and parts of NSW. Swimart has some key tips to help pool owners reclaim and clean their pools – and thus mitigate further damage and eliminate contaminants.

“Our thoughts are with those affected,” says Graham. “We understand the number one priority is cleaning out houses and making them habitable, but it must be remembered that flooded swimming pools present a unique set of hazards.

“It’s certainly not essential that a pool must be restored to use immediately, but it is vital to assess the condition of the pool and make it safe before starting any work.”

The pool shell acts as a kind of ‘boat’ when empty of water. If the surrounding soil is saturated, the pool will have a tendency to float, which can cause it to shift or crack.

“The fact is that all swimming pools – whether they’re vinyl-lined, fibreglass or even concrete ones weighing over 50 tonnes – can float when empty. The upward pressure of the water under the floor can actually cause it to lift,” he says.

Most pools are equipped with a hydrostatic relief valve in the floor which will allow ground water to enter the pool to keep the equilibrium and relieve pressure build up. However, the valve could be faulty or not able to cope with the amount of pressure caused by the ground water. Therefore, it’s wise to consult an experienced technician if you must empty the pool.

With recovery efforts now underway, there are a number of integral steps to restore flood-affected swimming pools.

“An unused, flood-affected swimming pool is not likely to transmit or become a source of diseases in the short term unless sewage has contaminated the pool. However, as it generally won’t be filtered or sanitised, it is important to check for evidence of mosquitoes on a daily basis.”

Tips for owners of pools affected by floods and heavy rain:
• Determine whether fencing is intact to prevent children from accessing the pool;
• Secure or restrict access to the area if possible, particularly if fences have been damaged or debris has made the area dangerous;
• Do not empty your pool, as the ground water may have become saturated and the pool could pop or crack. Experienced pool technicians should only empty pool water when it’s deemed safe;
• Check the pump house and other structures in case snakes, spiders and other pests have harboured there;
• Remove all debris from the pool including leaves, branches and dirt as this organic matter will create algae issues;
• Have a licensed electrician check the circuits and electrical fittings of your pump, timer and any electrical equipment. This may need to be done in consultation with a pool technician in case electrical components need to be replaced;
• Consult with a pool technician on how to ‘flocculate’ the pool water. Aluminium sulphate, a flocculant, will cause suspended solids in the water to congeal into a filterable mass and settle to the bottom. The flocculated material should be vacuumed to waste and not filtered, as it will rapidly clog the filter;
• Take a water sample to your local pool store for testing and advice;
• Test the water pH and aim for a recommended range of 7.2 to 7.6;
• If your pool is full of water but isn’t able to be restored, check it daily for evidence of mosquitoes. If mosquitoes and/or larvae are detected, speak to a pool technician about how to remove them;
• If the pool water starts to turn green, an algal bloom is developing and you should consult with a pool technician about how to address this;
• Only turn your filter back on once water quality has been restored and an electrician has checked your equipment.


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