What to Do to Your Pool After It Rains

Before a storm rolls through, it is important that you cover your swimming pool and shut off the pumps. It is easy to prepare your pool when there is adequate warning, and you can get everything nice and secure before it hits. The problem, though, is that storms are unpredictable. They can come in the middle of the night or during a weekday when you are at work.

In the event you get surprised by a storm – or you just forget to get everything covered – there are some simple things you can do to get your pool back into safe swimming condition. After the storm has passed, make sure you go through these three steps.

Clean the pool.


In many cases, rain storms rarely come without wind. Leaves, branches, twigs, and even lawn ornaments can blow into the pool, dirtying the water.

Begin cleaning the pool by brushing off the steps, walls, and behind the ladders to make sure that nothing will fall in after you’re done cleaning. Remove the largest items by hand if needed, and then skim the rest of the debris out.

If you have a pool vacuum, pull it out and clean what you can. Turn on your filters once the items that can clog them are gone.

Check the pH and alkalinity levels.


The chemical levels in a pool are meticulously maintained to ensure that swimming is safe. A little bit of added rain water in the pool isn’t going to off-set the pH and alkalinity levels much.  If there is a lot of rain, acid rain, or too many contaminates in the water, however, it will call for some chemical adjustments. Here are some things to keep in mind concerning your pool’s pH and alkalinity:

    • pH – Rain can cause your pH to drop, especially after a big storm.

    • Alkalinity – Alkaline water has a higher pH level than regular drinking water and rain tends to make it more acidic.

    • Sanitizer – Your chlorine or alternative sanitizer needs to be at the right level to help fight off any contaminates that may have entered your pool with the storm. Check the levels and add more if the rain watered them down.


Sometimes rain is a good thing, though. If your alkalinity or stabilizer levels are too high, the only way to bring these levels down is by adding water, so rain can help your maintenance woes in some cases.

Not that this is something you want to rely on. You should be the one controlling those levels at all times to ensure the best swimming experiences.

Always test the water after it rains so you will know what adjustments you should make.

Restore balance if necessary.


Small amounts of rain, such as  .25” and .5” can temporarily drop the pH levels in your pool. The proper balance is quickly restored.  After large storms, which add 2-3 inches of rain water to your pool, you’ll have to add chemicals as needed and wait to make sure they don’t adjust too high.

Restoring your pool’s proper balance will require more than just adding chemicals. You will need to drain the pool to its normal level first and then re-test the water. Make any necessary alterations to the pH or alkalinity when the water is at the right level.

Many pool owners like to shock their pool after a big storm, but this isn’t always necessary. Normally shocking the pool is only needed if there are abnormally high levels of contaminants from a destructive storm. No harm will be done to your pool if you choose to shock your pool. Don’t feel like it’s standard after-storm procedure, however. If you feel like you need some help testing and adjusting pool levels, don’t be afraid to call in a professional.
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