There’s nothing more satisfying than jumping into cool, swimming pool water on a hot summer’s day.
Whether we’re at public pools, in our backyard, or on vacation in the hottest of countries, taking a dip in those clean, blue waters is the best part of the season.
But, while you’re doing your laps or playing water polo or annoying your family by splashing them, have you ever stopped to wonder why exactly swimming pool water is blue?
Think about it… The water we drink is clear. The water we bathe or shower in is clear. So, why are our pools different?
Of course, you can search elsewhere for the answer to this question on the internet, but in return, you may be faced with many myths as to why pool water is blue.
Many people come up with all kinds of theories to this question. However, the answer to this is a lot clearer than you think!
In this article we will tell you exactly why swimming pool water is blue, we will also delve into a few of the myths to try and dispel them.
Read on for more!
Table of Contents
- Why Swimming Pool Water Is Blue: The Myths
- Why Swimming Pool Water Is Blue: The Truth
- Why Is Your Pool Water Not Blue?
- How Can You Keep Your Pool Clean?
- Our Final Thoughts On Why Swimming Pool Water Is Blue
Why Swimming Pool Water Is Blue: The Myths
There are many myths circulating the internet as to why pool water looks blue. Let’s delve into a few and see if we can clear them up!
1. Pools Are Blue Because Of The Sky
Blue skies, blue pool water, right? Wrong.
Many people think that because pool water is reflective, it reflects the sky and this makes it blue.
This is a myth. After all, an indoor pool is blue, too, right?
2. Swimming Pools Are Painted Blue
This is a popular theory as to why swimming pool water is blue, but it couldn’t be further from the truth.
Yes, many pools are painted blue at the bottom.
However, they are also painted white and a combination of both colors.
Additionally, these days, pool technology allows pools to have a more natural finish – as well as unique finishes, too!
This has resulted in porcelain, glass, and simulated stone pool bottoms.
However, all of these pools have blue water, and none of them are the cause!
3. Pools Are Blue Because Of Chemicals
Again, this is a myth as to why swimming pool water is blue.
Chlorine is generally added to pools to help keep them clean and clear, but it does not dye the water at all.
The healthiest pools are clear pools.
Why Swimming Pool Water Is Blue: The Truth
Here is the real reason why your pool water looks blue.
It’s All In The Science
So, what do you need to know? Well, the first thing you should know is that there is no such thing as “blue” water.
The truth about why pools are blue is much simpler.
When light hits the surface of a pool, the molecules absorb red light. This causes your brain to interpret the reflection as being blue. The water appears bluer the deeper it is, too!
If you look up into the sky, you’ll see that the sun creates a similar effect on the clouds.
So, if you’re looking down into a swimming pool, or even up into the sky, it appears blue.
If you were standing next to an ocean, however, you’d notice that you will sometimes be looking back at green water.
That’s because the oceans reflect green wavelengths of light.
A Combination Of Factors
There are some truths to the myths that certainly help it to look that way, too. The finish of a pool, no matter if it’s glass, simulated stone, etc, is designed to make the water appear bluer than it is.
Additionally, the use of chlorine in pools helps to make the water clean, which in turn helps the light to absorb and reflect the way it does.
Ultimately, pool water is blue because of the science of light.
Ultimately, pool water is blue because of the science of light but these myths do help the appearance of the pool in their little ways.
Why Is Your Pool Water Not Blue?
Sometimes, pool water can look anything other than blue.
You can sometimes be faced with a green pool, or even a brown, murky pool. Sometimes, the color of the tiles does affect the pool but this is usually because of other issues to do with the pool, such as the presence of algae.
One of the most common problems is that your pool pump is not working properly.
Another problem is that your skimmer basket is clogged. These two things are easy to fix so check them first.
If these two items aren’t the culprit, then try checking your filters and cleaning them.
If you do not have blue pool water, then it’s time to clean your pool!
How Can You Keep Your Pool Clean?
You need to make sure that you don’t leave algae behind in your pool.
Pool algae grow quickly in warm temperatures and will grow faster in warmer weather.
To combat this, you should use a chlorine-based cleaner to kill off the algae before it gets out of hand. You can also use an appropriate amount of algaecide or a filter to remove debris from your pool.
There are other ways to keep your pool water clean, too. For example, you can add salt to the water as an alternative to chlorine.
Salt kills bacteria and prevents algae growth. This is especially important during the summer months.
Additionally, you can buy a pool vacuum system to help get rid of leaves and other debris. A good vacuuming system will take care of the majority of your pool maintenance needs. See our list of the best vacuums for Intex pools!
Our Final Thoughts On Why Swimming Pool Water Is Blue
For many years there have been a wide variety of rumors circulating the internet as to why we all have a blue water swimming pool.
Some have said it’s because of the dye from chlorine, while others say it’s because of the color of the sky reflecting into the water.
The truth to what turns pool water blue is a lot more scientific, and it’s all to do with light.
As we stated above, pool water is blue because when light hits the surface of the swimming pool, the molecules in pool water absorb red light. This reflects blue light, which is what we can see, and it is as simple as that!
Check out the helpful video on how to keep your swimming pool blue and aesthetically pleasing year round as well!
My name is Denise and I am an Analytical Chemist located in the Kansas City metro area. Some things I am passionate about are gardening, science, swimming, and blogging. I am happy to be part of the All About Pools team & contribute my knowledge & expertise to help swimming pool owners and backyard enthusiasts!