You open the door out to your pool deck, expecting to see a crystal clear pool after cleaning it and shocking the pool the day before. But the rusty brown pool water you see instead doesn’t match that image at all, and you have no idea what’s wrong.

The first time this happens to you is upsetting, especially if you thought you had done everything right to get the water ready for your family. Let’s find out what causes pool water to turn rusty brown.


What Causes Brown Pool Water, Anyway?

The short answer is the water turns brown due to metals that oxidize in pool water. That can definitely be confusing to a new pool owner because how do metals even get there? 

What happens is this: After you shock the pool with chlorine, the water (and even pool parts) may turn brown and sometimes even green or black. The brown color alerts you that Iron is in the water, one of the most common metals that finds its way into pools. The chlorine is reacting to the iron, so it’s a case of the shock plus the iron equals brown water.


Other Strange Colors That Can Happen

Copper is another common metal found in pool water. It interacts with the chlorine used to shock the pool just like iron does, except it will turn the water a light green color. Then, there is Silver, which turns black, and both Manganese and Magnesium which turn purple. 

Add to this the fact that the green color in a pool can also mean an abundance of algae in the water. It’s no wonder you are confused, wondering “Is it algae or copper in the water?”

Read on for more information about these strange color changes in your pool water. And how Pool School Videos can help.


Where Do These Metals Come From?


why did my pool turn brown after shocking it | metal in pool water


It’s a natural question: Where in the world do metals in your swimming pool come from? Here is what you need to know about the sources of metals in your pool:

Pool Chemicals with Heavy Metal Components

Many pool products you purchase routinely have heavy metals in them. Some algaecides contain copper and over time the metal accumulates in the water, causing the green color as you routinely use chlorine shock. 

It’s true that pool owners sometimes feel they have to become chemists to maintain their swimming pools properly. This is certainly an example of that frustration. The first step to understanding the problems of pool water turning a rainbow of colors is to pay attention to the chemical composition of your pool products. Read the labels. And then you can try and avoid products that might cause problems in your pool, now that you know what they are.


Water from a Well or Some Municipal Water Sources

Is the water you use to fill the pool coming from a well? If so, you are most likely putting copper and iron into your pool each time you add more water. Iron reacts with chlorine to form iron III chloride, which is red. Once this reaction happens in a large amount of water, the red turns rusty brown. Some municipal water supplies also contain copper and iron.

If your swimming pool is near a mine, the well water can contain other metals like silver, manganese, and magnesium. The pool water may then turn black or purple. Not a good look for your swimming pool!

why did my pool turn brown after shocking it | rusty brown pool from well water

Metal Pipes and Pool Parts

As a swimming pool is being built, pipes and heaters are often used that are made of metals like copper, iron, or silver, as well as some other metals. Copper in particular can be a problem because water with a low pH can corrode the metal into the water. It then oxidizes with the chlorine shock you use and soon your pool water and pool parts are green.

According to an article from Commercial Industrial Supply on piping for pools, “copper piping is no longer recommended for use in pool installations, but it can still be found in older pools that were installed before PVC pipe began being used.”

Most pool owners don’t pay much attention to the pipes being laid as their pool is constructed, or maybe the pool was already there when they bought the house. It’s good to know the kind of pipes your pool has so you will understand how it stands up to a variety of issues, like copper pipes and how the copper reacts to chlorine shock. 


Pool School Videos Can Help with Rusty, Black, Green, or Purple Swimming Pool Water!


clearing up a rusty brown pool | why did my pool turn brown after shocking it


If your pool water has turned rusty brown after shocking it, don’t worry. It can be corrected! Pool School Videos is committed to providing in-depth, understandable information on both common and not-so-common pool maintenance problems. Pool water that turns unusual colors mystifies most people, so you need expert information to help solve the problem. 

A pool that is properly maintained offers your family and friends a safe, enjoyable experience. Imagine having an expert like the “Pool Doctor” Mike Steele, with over 30 years of experience in the pool maintenance industry, available to assist you in maintaining the relaxing environment you want to create for your family and friends.

For example, Pool School Videos has a video that explains exactly why your cloudy pool is not clearing up, how to figure out what is causing it, and how to correct it. Our program consists of a total of 20 self-paced, online pool maintenance videos that provide specific, easy-to-follow information on how to properly take care of your pool. Like you won’t find anywhere else!

Pool School Videos provides you with the tools to solve any pool maintenance problems that you might have as well as tools to prevent future problems. With these videos, you will save both time and money, giving you more opportunity to actually enjoy your pool instead of spending hours maintaining it. Once purchased, the videos become yours, so you can watch them as many times as necessary.

You also get access to our private Facebook Group as part of your Pool School Videos purchase. Through this group, you can request customized guidance by posting specific questions that you may have. We will respond within 24 hours!

Click here to preview our top 5 videos and meet the Pool Doctor, Mike Steele. And then get started on Pool School Videos today!

* Article feature image source: AquaClarity