Flooded pools — do you know best practice?

SPASA Victoria

By William Mansfield of BioLab Australia — on behalf of SPASA Victoria
Thursday, 07 December, 2017


Flooded pool

How do you remove potential contaminants such as clay, dust and debris from flood-affected pools? William Mansfield of BioLab Australia put together the following information for SPASA Victoria. It represents the best interpretation of available technical information at the time of preparation.

If a pool has been susceptible to heavy rainfall, it is likely to have gained plenty of dirty water, mud, debris and other various contaminants from the surrounding environment.

Although a dirty, clouded and flooded pool is a huge inconvenience, the pool can be used soon after if it is treated promptly, after the weather subsides. The following procedure is recommended to rectify flooded pools.

  1. Check the pump, filter and other mechanical parts of the pool system for damage. If there is any damaged equipment, see the applicable manufacturer for instructions or replacement parts.
  2. Remove all debris from the pool. The rainfall has probably brought in leaves and other debris from the surrounding areas. This will add large amounts of organic matter to the water, which in turn will cause issues with algae and chlorine residual. The sooner rubbish is removed from the pool, the sooner clean-up can begin.
  3. Use a high-quality floc to drop the clay and dust that has clouded up the pool to the bottom. Remember that overdosing with a floc will not make the job work faster.
  4. Vacuum the debris formed from the Power Floc to waste.
  5. Turn on and leave on the pump/filter until water balance has been achieved. From now, much of the debris should have been removed from the water. Although still cloudy, the filter is the easiest way to clean the water.
  6. Test for metals and treat accordingly. The pool water may look a lot clearer than the start, but there may be many dissolved particles within the pool that came in with the dirt and clay. If there is a residual of metals (copper/iron) it can cause permanent staining, especially when chlorine is added back to the pool.
  7. Test for chlorine demand and treat accordingly. The flood water has washed an incredible amount of organic and inorganic material into the pool. Although most of it has been cleared out, there are still large amounts dissolved within the water. These particles can cause a huge drain on the chlorine added to the water to keep it healthy.
  8. Treat the pool with high-quality algaecide. The chorine is what makes the pool healthy to swim in, but as the chlorine is working at oxidising, the pool needs to be protected from algae. This defends the pool from algae while the chlorine is working at oxidising and killing bacteria. Once a good chlorine residual has been achieved, go back to a maintenance dose of algaecide.
  9. Use a clarifier. By now the water should be holding a chlorine residual, so that the filter can be utilised to collect dead algae and other oxidised organic waste.
  10. Manage the water balance. The water should be tested again by a professional pool shop. The chemicals just added to recover the pool will have had an effect on the water balance. This is because the pool has just been flushed with new (dirty) water. The water needs to be balanced again as it is the most important step to keeping the pool healthy, sparkling, clean and inviting.
  11. Use a clarifier one last time when the water is balanced. Although the water may look beautiful and fresh, the addition of one last clarifier will really bring the sparkle back to the water.
Related Articles

Flooded pools — do you know best practice?

How do you remove potential contaminants such as clay, dust and debris from flood-affected pools?...

Australian chemical compliance with GHS

Most states and territories have mandated the use of GHS compliant classification, labelling and...

Common pool industry personalities

The swimming pool industry is full of interesting personalities and anyone who has worked in the...


  • All content Copyright © 2017 Westwick-Farrow Pty Ltd