Oh No! Why Is My Pool Green?

Oh No! Why Is My Pool Green?

October 7, 2021

There’s nothing quite like the inviting blue hue of a swimming pool on a hot summer day. The visual itself is a key part of the total package of having a swimming pool. Maintaining your pool is a labor of love… until one day you find that your pool’s water is green.

So, what happened? You understandably want to know what green pool water means. Any pool owner would. This article will cover some possible reasons why your pool water is green.


The uncontrolled and unwanted growth of algae is the most common cause of your pool water turning green. It naturally grows in water, and you’ve probably seen it in ponds or streams. But your pool water is treated with chlorine, and that’s supposed to kill any microorganisms that might be harmful to humans.

So, the problem of algae growth likely stems from a chlorine imbalance in your pool. You should be checking the levels of chlorine regularly and making sure there’s enough in your pool. You likely need to add some chlorine and algaecide to fix the problem. Wait until 48 hours after the water is completely clear to start swimming in it again.


Another possible cause of green pool water is pollen. Plants and trees that are near the pool produce pollen, which is subsequently carried by the wind and dropped into the pool. The main problem with pollen is how small it is.

It’s small enough that a standard pool filter likely won’t catch it, and this allows it to build up over the entire season while you’re using your pool. The pollen may build up on the sides and look like green or yellow algae.

The good news is that pollen isn’t harmful to humans, and it can usually be remedied by using a pool flocculant and manually cleaning it out.


The presence of metals in the water can cause it to become green. Copper is usually the culprit. The metals can get into the pool through the source water, algaecide products or the metal components in the pool themselves. There are metal components in your pool’s heater, and these are usually the issue.

You also must be careful when applying shock treatments to your pool. This is because the chemicals you introduce into the water can have an oxidizing effect on any metal components in your pool. This reaction can turn the water green.

Green water caused by metals has the potential to permanently stain the finish of the pool in addition to turning any blonde-haired swimmers’ hair green, so be sure to address this problem right away. Using a sequestrant, which binds the metallic particles together and makes them easier to filter out, you can rid your pool water of those pesky excess metals. You’ll also want to backwash and chemically clean your filter once you’ve applied the sequestrant to complete the process.

Call for help with green pool water today

This is by no means an exhaustive list of reasons explaining why your pool water is green. But hopefully this article lets you know what green pool water means if you ever find it in your pool. If you’re unsure of what to do with your pool’s green water, you can always call us at A-1 Pools & Spas. Our experts can not only help you fix your pool’s green water, but we can diagnose the problem and help you prevent it from ever happening again.

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