Why is my water that color?

As someone who works in water treatment I fequently receive questions about red, black, pink or cloudy appearances in drinking water. Contrary to what might be expected none of these colors are inherently dangerous to human health. They do however make the water look unappetizing. They are called asethetic water quality indicators. Well the colors themselves isn’t the indicator, what causes the water is. I will outline the causes below.

Red water is usually caused by the oxydation of iron and iron bacteria. To be a little more accurate the color is a reddish brown, if you see a red that belongs in a paint can then I highly recommend NOT drinking it. Iron oxydation (rust) is not dangerous at all. Many water sources contain iron naturally. Iron is prevalent in groundwater. The red color comes from iron particles rusting when they come into contact with oxygen in the water. The rusting is accelerated when the iron is introduced to chlorine. As you know chlorine is very commonly used as a disinfectant. When there is a lot of iron and a lot of chlorine then there can be a visible particles of rusted iron in the water. This looks really bad when you turn on the faucet but iron is something they add to mineralized bottled water and iron is a necessary element in proper nutrition.
Iron bacteria can enter the water at the source or if the water is stored in a metal container or watermain. Wells can become contaminated with iron bacteria. When they do, read this to know what to do about it.

Black colored water is not to be confused with black water which is a term used for sewage. Sewage is often a yellowish brown, unless it has gone septic and then it is very black and very smelly. An odorless black tint to water is usually due to manganese. Manganese behaves a lot like iron does except it oxidizes a lot slower. Water stored for a couple days or more will turn black if there are high levels of manganese in the water. Manganese is more often found in groundwater than in surface water. Sometimes it wont be noticeable in the water. It will however be noticable as a black stain on appliances and reservoir walls.

Pink water comes from potassium permanganate (KMnO4). Permanganate is a treatment chemical used to help oxidize iron and manganese. When too much is added the water turns pink. When a lot is added then the water turns purple. The pink isn’t dangerous to human health. It is hower alarming to see pink coming out of a faucet. To read how to use potassium permanganate as a disinfectant read this.

To remove iron, manganese and permanganate is accompolished with greensand filtration. Don’t let the name fool you, greensand is black in color. Greensand is chemically activated to remove oxidized minerals from water.

A yellowish tint (sometimes brown) to the water IS potentially dangerous. Yellow tea colored water is indicative of organic material in the water. Organic material is mostly non living particles but it also includes bacteria, viruses, and other pathogens. Sewage is also this color. So beware of yellowish water.

Not many different things can cause a truely cloudy appearance to water. Turbidity is sometime said to be “cloudy” but it is caused by suspended particles blocking light from passing through. Usually turbidity is also colored at the same time. Unless the particles are white in color, then turbidity isn’t cloudy, it is dirty.
Cloudy water is caused from dissolved gasses (usually oxygen) in the water getting released. This happens when the temperature in the water is significantly different than the temperature of surrounding environment. Since large bodies of water are slower to heat up and slower to cool down, this difference happens every spring and fall. It is called reservoir turnover. The way to test if it is just dissolved gasses in the water is to let a glass sit for five minutes. All bubbles of gasses will disappear and the water will look and taste normal. If the water is still cloudy after five minutes, then the problem is caused by turbidity and it must be removed by filtration.

Not everything that can happen to drinking water is dangerous. Reddish tints from iron and blackish tints from manganese are natural and harmless. This article should help you determine when visual changes to the water are cause for alarm and when they can be ignored safely.

8 thoughts on “Why is my water that color?

    • It could be the filtration system from your water treatment plant. Pink water is also an indicator from to much Flouride. If you don’t call them to fix it they won’t change anything. Not everyone is smart or cares. This article isn’t very helpful and actually just dumb. water should be clear and taste good at all times. It could be your pipes too. It’s not the waters fault hardly ever. Water has a way of self cleaning and being just wonderful and spectacular. Dirty water is caused by water treatment people at the plant not doing their job or your pipes. Just like the problems happening over at so and so about the lead. That’s the pipes not the water source. Water costs billions and billions and billions all the way to the trillions for fresh water. Demand great water because like I said its one of the two, Bad pipes or water treatment plants.

  1. Since installing a chlorination system, my water has become tinted yellow. It would seem that the sodium hypochloride is causing the color to change by reacting with something in the water. I installed a media filter, but it has not [made much difference. What can I do?

  2. what about water turning black than normal in more than one sink in the house??? anyone please help???

  3. Yeah well I know pink water could indicate to much Fluoride and I don’t recommend drinking any water if it’s not clear. Boiling water before consumption might be best. But I don’t know if that makes it safer to drink after boiling. Lately I have noticed my water is more merky, bubbly, soapy, overly chlorinated, and overly flourinated. Who ever is running our water treatment plant sucks. Water should be clear coming from the water treatment plant and barley treated with anything except for chlorination. Ground water is perfect and shouldn’t need much treatment. Pipes are the main thing that can cause rusty water. But bubbly water or overly chlorinated water is the persons fault at the water treatment plant. My husband is a rural water guy who installs large pipe and yes the water treatment plant needs to be paying attention how their treating the water. Bubbly water soapy water brown water pink stinky water is their fault and I don’t recommend drinking the tap water until it has been cleared up. Water is blue but should come out clear from the tap. If a leaf gets into a pipe that could make a huge water leak. Like in the last year my water has been disgusting compared to what I’m used too. It’s the person treating the water because my pipes are brand new and done correctly. PINK WATER way to go.,….,I’m not used to this. I’ve been used to great water even though it’s chlorinated.

    • Chlorine is poison and is always used in public water systems. Fluoride is even worse poison and has been removed from most municipal water treatment facilities. If your water supplier still uses Fluoride, I would absolutely NOT drink it. There has been studies for the last 30 years that prove it does not improve tooth health, although it is the root of a host of modern day issues. Chloride is virtually bleach. Would you willingly drink bleach? You are if you have municipal water.
      Do yourself a favor and research Fluoride and Chloride in water, And get a quality whole house filter for sure.

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