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Why Is My Toilet Water Blue?

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

While it is not the case for every toilet, there is a very high chance that you have at least seen a toilet that has blue-looking water in the bowl.

This may have led you to wonder what the reason for this is, and what is the difference between toilets with blue water and those that do not.

Toilets, of course, are one of the most commonly used parts of a household, so because of this, it is important to know exactly how they work to make sure they do not fail on you.

Toilets allow humans to display a high level of hygiene and cleanliness, but if we do not look after them properly these appliances can succumb to overuse and need replacing or fixing more often than they should.

Make sure you are actively checking the state of your toilet regularly to make sure this will not happen and that you can prevent problems instead of having to fix them.

So back to the main topic at hand, why is toilet water turning blue, and is it a sign of a problem that is being caused?

What Is Making My Toilet Water Blue?

If your toilet water is beginning to appear blue, the majority of the time, it can be explained simply by three different variables. Let’s go over them, so you can see if any of these may be affecting your toilet.

Corrosion In Your Copper Piping

When this happens you can end up with either green or blue water in your toilet bowl. When copper oxidizes it creates Copper oxide which has a green/blue color and can wear off into the water going to your toilet which will cause the color change.

Having pipes that have severe enough corrosion damage to cause a problem like this is a large issue and will need to be dealt with quickly to save both your piping and your toilet.

Using Blue Toilet Cleaner Tablets

Those who like to keep their toilets as clean as possible will sometimes use cleaning tablets that are usually put in the tank behind the toilet to clean it.

The tablets have chemicals included that are designed to stop the water from staining porcelain and lower the odors that can come from toilet water. These tablets are also useful in stopping the creation of mold or buildup of limescale.

Above Average Copper Content In Your Water Supply

This issue is famous for happening in areas like Minnesota as they just naturally have a higher copper content in their water. This problem as you can imagine is completely out of your control to solve. But you can stop it from affecting you personally by purchasing and installing a water filtration system to stop this water from entering your home.

What Will Cause A Blue Ring To Appear In A Toilet Bowl?

This is a slightly different issue to that which was previously discussed, for this issue, instead of the water itself appearing blue, a blue ring will rim the bowl at the level at which water usually rests but can also manifest in blue stains higher up the bowl.

If you do not try to prevent this issue, it will inevitably expand a cover a higher portion of your toilet bowl.

Similar to one of the causes of blue water, this issue is a byproduct of three being too much copper in your water supply and will make your toilet water significantly more acidic than it should be. While the overall quality of the water is not too harshly affected by this copper content, it will cause the aforementioned stains to appear.

What Other Colors Can Toilet Water Turn Into?

What Other Colors Can Toilet Water Turn Into

While blue is one of the more commonly recognized colors toilet water can turn into, it is not the only one, and depending on the color this can signify varying different problems with the toilet water. So what are these other colors, and what do they signify?

Red, Brown, Or Orange Toilet Water

If your toilet water has turned either red, brown, or orange, the cause of this problem is actually more obvious than it would originally seem.

This issue is nearly always caused by rusting in your plumbing system, usually from rust on galvanized iron or rust on your steel plumbing. Plumbing systems tend to contain iron oxides if your protective layer of zinc wears out.

This problem can actually cause quite a lot of issues on top of the appearance, it can affect the taste of food made with it, and it will even stain a lot of what it comes into contact with like clothes. It can also cause a rust deposit when it appears in toilets.

Green Toilet Water

Green toilet bowl water is most likely caused by corrosion in your plumbing along with an algae accumulation.

Clearing a plumbing system from algae is not too difficult to do, but if the copper corrosion (see also ‘Copper Corrosion: Everything You Need to Know’) is the cause this can be more awkward and will likely require the help of a professional. If you consume this green water in any capacity it has the possibility to cause health problems.

Yellow Toilet Water

If your toilet water is appearing yellow this is most likely caused by repairs and cleanup done at a local water distribution center.

Pink Or Purple Toilet Water

If your toilet water is appearing pink this is likely an indicator of the presence of potassium permanganate, a product used in oxidizing iron as well as manganese. If it intensifies even further the water will eventually turn into a more intense shade of purple.

Black Toilet Water

Now if water is turning black this is an indicator of the growth of mildew within your plumbing system and will require the help of a plumber to fix. Do not consume this water as it contain unhealthy amounts of mold and will be harmful to your health.

Is Blue Toilet Bowl Water Dangerous?

If your water is blue because of a high copper content we can be led to wonder how copper content will affect our health.

How Does Copper Affect Our Health?

If you ingest excessive amounts of water tainted with copper this can cause a variety of health issues including; diarrhea, vomiting, nausea, liver damage, stomach cramping, and even kidney disease.

These effects will be even more dangerous to children under the age of one as their bodies have not developed the proper abilities to combat the substance entering their body. This is why water filtration systems come highly recommended.

How Does Blue Toilet Water Affect Our Plumbing?

The blue water is not what is harming your plumbing systems, but instead a sign of damage that has been done to it, almost always by corrosion. This indicates that you will need to get your copper pipes (see also ‘Why Do Copper Pipes Turn Green And How To Clean Them?‘) fixed or more likely replaced, if your copper pipes have repeated issues, some homeowners recommend plastic piping as an alternative.

What Are The Pros And Cons Of Using Blue Toilet Tank Tablets?

The other most common cause of blue water is toilet cleaning tablets, while the blue water itself is not really an issue in this case, what are the benefits or drawbacks of using these products on your toilet?


The main reason to use this product is to keep toilet water fresh smelling and clean. They are convenient to use as they can easily just be put in the toilet tank and are largely waste free. These are the main reasons to use this product, however there are some variables you should consider when using them.


Unfortunately if you excessively use this product it can damage the lifespan of a lot of the parts of your toilet due to the presence of harsh chemicals. They particularly damage the flush valve and flapper as well as making rubber pieces of the toilet significantly more brittle.

These tablets are also not particularly environmentally friendly and if you are not connected to a city sewage system the chemicals in the tablets can contaminate soil that surrounds your septic tank. Also inhaling too much of the chemicals can cause issues as well.

Finally, if you have pets it is recommended that you do not use this product as if they ingest the blue toilet water, especially if they ingest too much it can become dangerous to their health.

Summary – How To Stop Your Toilet Having Blue Water

So now you know all the potential causes for blue toilet water, you can tell that unless this is the impact of your choosing to use toilet cleaning tablets, it is nearly always a negative.

If the cause is corrosion in your pipes it is recommended to contact a professional as soon as physically possible to save any further damage, and if it is caused by a high copper content water supply, then it is maybe time to consider investing in a filtration system. Some good quality filter systems worth considering are; ion exchange filters, reverse osmosis filters, or activated carbon filters.

And even if you caused the issue by using cleaning tablets, maybe reconsider if you are worried about any of the listed cons.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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