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What do you actually do with the pool water after a heavy rain shower?

Rainwater can be acidic and affect the pool pH. After a particularly heavy rain, you will have extra water in the pool that will change the pool chemistry.

If it’s a light shower, you don’t have to worry about pool chemistry. If it rains just a little, it will have very little effect on the pool water.

In the event of a heavy downpour, you should follow the following tips. For a short downpour, some steps are not necessary – but won’t hurt either.

Prepare the pool for a heavy downpour or thunderstorm

Use the following tips to best prepare your garden and pool area for a heavy downpour.

Move garden furniture and pool accessories indoors

In the event of a stormy weather, all garden furniture, pool and swimming toys should be stowed indoors.

A powerful storm will otherwise create all sorts of chaos in the backyard. Furniture gets pushed back and forth, flower pots tip over and break, and objects get blown into the pool.

In any case, you should clear away:

  • Grills
  • Pool accessories such as buckets, water guns and floatation aids
  • Air mattresses and other swimming toys
  • Flower pots
  • Towels, loungers, chairs, awnings and umbrellas
  • Equipment for the cleaning and maintenance of your pool (pool nets, pool robots, pool vacuums, pool pump and co)
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Feadem Pool Skimmer Strong Grade
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Prepare the pool water

Can a pool overflow due to rain? Sure!

Therefore, before a heavy rainstorm, lower the pool water level by about 30 cm.

For some swimming pools, this is not necessary. Modern or in-ground pools are often equipped with overflows that drain the excess water.

Optional: We recommend adding some algaecide to the pool water. The algaecide helps fight organic contaminants that enter the pool through rainwater.

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Disconnect all power, water, and gas lines to the pool

Turn off the filter pump before a severe thunderstorm. If you use a timer for the pump, make sure the timer does not start the pump during the storm.

If you have covers for the filter or pump, we recommend installing them before the storm. Gas lines must be shut off to avoid the risk of a leak.

Leaking gas is a major source of danger. You can minimize the risk by making sure it is shut off properly and, at best, by additionally covering open gas lines.

Cover your pool with a pool tarp

A pool tarp prevents pollen, dirt, leaves, branches and insects from being blown into your pool. It makes cleaning the next day much easier.

Make sure that the tarp is well fastened. Then you won’t need a new pool cover the next time a storm hits.

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Clean the pool water after a rain in 5 steps

Once the storm has passed, you can clean the pool. If you have followed the tips and tricks for proper preparation, there is nothing to worry about, and the following steps will go quite quickly.

Step 1: Turn the pool pump and filter back on

During the storm, the power was off, and the equipment wasn’t working. Before you turn the pool pump and filter back on, remove all debris from the skimmer and pump baskets.

Once you have cleared the skimmer and pump baskets of debris, you cannot start the pump and filter again. Run the pump to filter out dirt particles that the wind has blown into the pool.

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Step 2: Clean the pool with a landing net

The easiest way to start is to use a pool landing net to remove the leaves and debris on the surface of the water.

Recommended
Feadem Pool Skimmer Strong Grade
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Note: You should do this before vacuuming the pool. When the dirt and leaves sink from the surface to the bottom of the pool, you have more work to do.

The whole pool area will be dirty. While cleaning, be careful not to get extra dirt into the pool. It’s best to use a garden hose to spray all the dirt away from the water.

Brush the steps and ladders of your pool so the vacuum or pool filter can pick up this debris.

Step 3: Use a pool vacuum

Now use a pool vacuum to clean the bottom of the pool. If the bottom is not too dirty, you can also use an automatic pool cleaner or a pool robot. If this is not the case, you will have to do it manually.

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Note: If it has rained a lot of water, the level in your pool may be higher than before. This is good if you need to vacuum a lot of debris from the bottom. If you used a pool cover and there is little or no debris on the bottom, you can get rid of the excess water by setting the filter to “Waste”, connecting a backwash hose, and turning on your pump.

Step 4: Observe and Test the Pool Water

First, test the pool water with a test strip to make sure the pH is in the correct range of 7.0 to 7.4. Rainwater and dirt particles can cause the pH to be too low.

If there is a major storm and a lot of debris in the pool, it may be a good idea to have professionals check the water quality. Who wants to end up with green pool water?

Rain brings impurities into the water. As a result, the level of disinfectants will drop. The concentration of calcium and cyanuric acids, on the other hand, will not be as affected by dilution from rainwater.

Step 5: Correct the pH value

Rainwater is more acidic. You will probably need to add pH Plus to bring the pH back into the ideal range of 7.0 to 7.4.

The pH Plus is available in granular, powder, tablet and liquid forms. All variants are simply dissolved in water.

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Should I shock chlorinate my pool after a heavy rainstorm?

Shock chlorination is not absolutely necessary, but it can help combat contamination.

Just make sure the pH and concentration of the sanitizer are at the right level. Then, the evening after the storm, add the pool shocker.

Avoid all work around the pool while the storm is raging. Due to the risk of lightning, do not swim in the pool either.

Conclusion

Rain brings dirt and can wash contaminants from your lawn into your pool. Follow our tips to prepare your pool for rain and use our checklist to clean your pool after a heavy rainfall.

After the storm has passed and your pool is once again crystal clear and free of debris, you can swim in the pool. We certainly hope your pool season is not interrupted by too many storms.

As always, we hope you enjoy your swim!

Larry has been a true water rat since childhood. Pure pleasure turned into a passion. That's why he is the first point of contact for friends and acquaintances when it comes to pool-related problems. He is an integral part of the PoolHandbook editorial team.