How to clean swimming pools after a storm or flood

Heavy rains, winds and natural disasters like floods can destroy the cleanest and most well maintained swimming pool, leaving the owner in disbelief of their tropical oasis. Severe weather can sweep dirt and debris into your pool, while floods can add an even larger amount of mud, silt, and contaminants.

At Mr Pool Man, we know it seems challenging to maintain a healthy pool after a storm or flood, so we have compiled these easy-to-follow tips below for returning your pool water back to crystal clear, no matter how dirty your pool might look.

Before anything else, do a safety check

It is essential to assess the pool and associated electrical equipment prior to commencing any work to ensure the safety of yourself and others. Once the floodwater / storms have receded the fence is the first point of inspection to ensure the safety of the pool has not been compromised. Restrict the area if there is any concern with electrical or fencing aspects until a professional can deem these as safe.

Main Issues we encounter after a storm or flood

We usually have three main issues that we come across after a storm and they are the following:

  • Debris, silt and soil washed into the pool
  • Phosphates and contaminants introduced into the water
  • Dilution of chemicals and salt levels causing water imbalance


So let's see what we can do about those shall we?

Steps on how to clean swimming pools after a storm or flood

  • Probably the most important thing you will read today, DO NOT DRAIN YOUR POOL as this can cause thousands of $$$$ in damage!
  • The second most important thing your will read today, DO NOT DRAIN YOUR POOL.


Caution needs to be taken when draining pools at this time as the flood water has made ground conditions around the foundations of the pool very wet. Pools should not be drained until ground conditions have dried to at least the depth of the pool as the entire shell of the pool (fibreglass or concrete) can “pop” out of its original position with the change in hydrostatic pressures.

Now that we have those two very important guidelines out of the way, let's go on to the rest of the steps on how to clean your pool after a storm or flood.

  • Scoop out as much debris as possible with a good leaf rake or leaf shovel. A leaf skimmer is fine, but if you want to save time and getting as much debris out of your pool as possible then a leaf rake or leaf shovel is the way to go.
  • After getting as much debris out from your pool as possible, clean and empty out your skimmer baskets and pump baskets. Don't forget the check your main drains as well for any stuck leaves or debris.
  • Reset your breaker to get your pumps ready for operation. In the event that your breaker doesn't reset, call a licensed electrician or your pool service provider.
  • Turn on your pumps and check the pressure on your pool's filters, if they're high, give your sand filter a good backwash or clean your filter cartridges before continuing. We're going to need them in tip-top condition to deal with a stormed out or flooded pool!
  • Take the opportunity to scrub out scum lines on your water levels when your pool is flooded! Since the water is already there, take a brush and scrub where your water level usually is.
  • If your pool is totally flooded, you can partially drain out the excess water down to the skimmer box level by setting your sand filter's multiport to "Waste" and run the pump until the water level drops. If you're using a cartridge filter then we recommend getting a venturi pump to help you drain the pool.
  • A venturi pump can quickly drain your pool without using your pool plumbing's system. And as an added bonus, it can also drain out other flooded areas and not just your pool!
  • Once that's done, shock your pool with UNSTABILISED Chlorine. If the flooding is particularly nasty then you may have to double the required dose. Read more on how to shock a pool here.
  • Leave the pool pump running for at least 24 hours and don't swim in the pool for at least 48 hours to ensure that every bit of biological contaminant is taken out by the chlorine. During this period, monitor your filter's pressure levels and test your chlorine levels to ensure that you have enough cleaning power in your pool.
  • If you have a salt water chlorinator, be sure to set it on maximum for at least 24 hours to help sanitise your pool.

Dealing with Cloudy Water After a Storm

After removing all the visible debris and shocking your pool, there's a big chance that your water will remain cloudy from all of the particles that have been deposited into the pool and are too tiny for your filters to catch. There's only one way to deal with this and that's through the use of flocculants and/or clarifiers.

Cloudiness is caused by small particles suspended in the water, these particles are smaller than 2 microns and will not get caught within the filter system. These particles are commonly negatively charged.

To remove these particles and restore clarity in the water you need to add a flocculant / clarifier to the water which are positively charged and bond the suspended debris together. Some debris that floccs together will float to the surface and capture within the skimmer / filter, the majority of the debris will sink to the pool floor where it is recommended to be manually vacuumed out of the pool via waste.

A key point to note is that flocc works more effectively with higher pH, so test your pool prior to adding clarifier or floc and ensure that the pH level is a minimum of 7.8. You can also raise the pH by adding Buffer to the pool which will also raise the Total Alkalinity.

Note: We don't recommend using flocculants with a filter cartridge so if you're doing this step, take out your cartridge filter when using a flocculant.

How to Apply Flocculants / Clarifiers to your Pool

  • IMPORTANT – Set your filter setting to RECIRCULATE. If you’re using an old cartridge filter or your valve isn’t functioning as it should, take our your filter cartridge to avoid damaging it.
  • Raise your pool water to its maximum level as you will be vacuuming out a lot of water after the treatment.
  • Dilute the flocculant in a 5-gallon container with pool water and broadcast it evenly around your pool
  • Allow the pump to run for a few hours to fully circulate the flocculant around the pool.
  • Turn off your pool pump and allow to rest for 8-12 hours (or overnight)
  • Set your filter setting to “WASTE”
  • Vacuum the particles that have settled down on the bottom of your pool
  • Backwash your pool filter / return your filter cartridge

The Pool Water Looks Clear, can we take a swim now?

Not just yet! We'll need to ensure that your Free Available Chlorine (FC) or sanitiser level is where they're supposed to be! After a storm, your sanitiser levels may be dangerously low and your chloramines will be quite high causing a dangerous lack of sanitising power! Give it good sanitiser treatment and shock with the Water TechniX Tri-Shock to effectively burn away any trace of algae, bacteria, and other pool baddies that may have come with the flood. And as a bonus, the green pool bundle that includes the tri-shock comes with a crystal clarifying cube that you can pop into your skimmer basket to help keep your pool water crystal-clear!

And on another note, it only looks clear but there are still some things lurking in the water that we need to deal with before declaring your pool back from the dead! The first one we need to do is add some phosphate remover.

Where there's leaves and other bio matter, there's sure to be a healthy amount of phosphates left. And in the world of pool maintenance, phosphates are a big no-no. You don't need to test your water for phosphates as we can guarantee that 100% you will have phosphates in your pool after a storm. Remove them and starve out the Algae before they have a chance to grow!

In tandem with a phosphate remover, we also recommend dosing your pool with some long-life algaecide as an added layer of protection. An ounce of prevention is better than a pound of cure! Or in our case, an application of algaecide and phosphate removers can save you hours of work and hundreds of dollars in pool maintenance work!

Check and Balance your Water

Another thing that we can guarantee after a storm or flooding is that your chemical levels will be out of whack! Make sure to test and balance everything after cleaning out all of the visible debris to ensure that your pool water is not only clear and inviting, but safe as well!

Don't Forget to check your Salt Levels!

If you're using a salt water chlorinator then it's very important to check your salt levels as well. After checking and balancing everything else, use some handy salt water testing strips and re-balance your salt levels to what your chlorinator needs. This is something that a lot of people forget after dealing with a flood. Many pools, especially those that are totally flooded will lose a lot of salt after a storm so don't skip this step!

Having a hard time following the videos? Check out our Green to Clean Post here where we walk you through every single step outlined in the video. 

Don't forget to clean your filters after a storm or flood

After all of that and your pool looks like a million bucks, don't forget the saying "out of sight, out of mind" and be sure to clean your filters afterwards. if you have a cartridge filter, be sure to hose down the filter elements, and if you have a sand filter, don't forget to backwash it.

Don't Let Storms Dampen your Summer Spirit

Don't let storms and flooding bring you down this summer season! Even if it's chilly, you can still enjoy your pool with the right know-how and equipment to deal with the flooding. If the muggy temperature has put a damper on your swimming season, you can consider getting a Water TechniX Paradise Heat Pump for your pool to keep it warm even though rains and flooding. For just a couple of bucks a day, you can keep your pool water warm and refreshing even through the worst storms or floods so that after a quick cleanup, you'll be back in your warm and refreshing pool in no time at all!

Caution needs to be taken when draining pools at this time as the flood water has made ground conditions around the foundations of the pool very wet. Pools should not be drained until ground conditions have dried to at least the depth of the pool as the entire shell of the pool (fibreglass or concrete) can “pop” out of its original position with the change in hydrostatic pressures.

P.S. Remember the image at the beginning of the post that looked like something from a disaster movie? This is the same pool being restored with the use of Water TechniX chemicals and advise from the Mr Pool Man team! Video coming soon!

Cleaning your pool after a storm or flood in a nutshell

Want something to put down on paper so you don't forget? Here's a quick list of what to do after a storm.

  • Scoop up all visible debris
  • Partially drain the pool (if needed)
  • Scrub down all of the surfaces
  • Apply a clarifyer / flocculant to the pool
  • Check and balance the pool water
  • Apply phosphate remover and algaecide for protection
  • Rinse out your cartridge filter or backwash your sand filter


So there you have it! Revive your pool after a storm or a flood easily. And if you're looking for a single solution to reviving your pool after a flood, just grab the Water TechniX Storm and Flood Pool Chemical bundle, no more mixing and matching of chemicals. All of the bare basics you'll need to turn your pool from green (or muddy brown) back into a crystal clear slice of paradise!

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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