The Colors of Tap Water

It happens. You turn on the faucet to get a refreshing glass of H20, and what drops into your glass sort of reminds you of that fish tank you had as a kid. You know, the one with the dead fish?

When your water isn’t clear, a person should always ask why. Considering we often drink it, bathe in it, brush our teeth with it, wash our clothes in it, and often put it in our food, it is in our best interest that it is safe and free of contaminants.

So, here are a few colors that should always throw up a red flag when it comes to faucet water.

Note: The following relates to public supply water. If you are having problems with well water, please consult your local board of health.

Brown, Red, Orange, or Yellow

Rust is usually the culprit in this situation. The different colors are due to the different chemical oxidation states and concentrations of iron (and rust) in the water.

There are two main reasons this happens:

Water pipes. The more serious cause is rusty water pipes inside your building. Copper pipes usually last longer and tend to maintain optimum water quality as they age, but galvanized steel pipes are more common and also more prone to rusting as they age. Thus, older (or poorly made) galvanized pipes can discolor your water to brown, red, orange or yellow. The only way to solve this problem is to replace the pipes.

But before you shell out the dough for new pipes, look for indicators that the discoloration is indeed due to the pipes. Ask yourself the following questions: Is the water discolored every morning when first used? Is the water clear after running for a few minutes? Is the discoloration only at one or a few faucets, not all of them? Does the discoloration only appear in hot water? If you answered yes, to these questions, your pipes are likely the issue.

Water mains. The less serious cause of brown, red, orange or yellow water is an issue with outside water mains. Normally, sediment is removed from your public filtration system. Sometimes the mains in low-flow areas (with aging pipes) can build up rust and sediment, which can discolor the water. Sometimes the water mains actually break, which can cause unusual water flows that can contribute to rusting. And sometimes, just a fire hydrant being used or knocked off by an accident can cause such problems.

There are some indications that the discoloration is due to water mains, rather than your home’s own water pipes. For instance, was the water clear earlier but then suddenly discolored a ltitle later in the day? Is it just the cold water that is discolored? Is the water discolored in all of your water faucets? Does the water not clear or improve after fun for a few minutes? If the answer is yes to any of those questions, the problem likely lies in the water mains outside.

Water this is discolored by rusty pipes is not a health threat and will not make you, your children, or pets ill if consumed. The main problem with this is it can stain your clothing. Wait several hours for the water to clear before you do your laundry. If it’s too late, wash the clothes again with a rust stain remover or regular detergent, but do not use chlorine bleach. Avoid using hot water, as you can draw rusty water into your hot water tank that you will have to flush out later.


In May of 2012, there was a big story about the residents of St. Michael, Minnesota and their pink water. The cause? Potassium permanganate.

Credit: Kim Walden

Potassium permanganate is a chemical that is added by water treatment plants to remove iron, manganese, sulfide odors, biological growth and color from public water supply. In the case of St. Michael, a pump feeding the chemical accidentally added a bit too much into the supply, causing the alarming pink color that might cause one to think their home is haunted.

Shades of pink can vary. It could be a distinct “Pepto” pink, or a cotton-candy-like pink like the image on the right, or a deeper, fuchsia hue.

Not that anyone would want to drink it anyway, but it is actually not dangerous to drink pink water caused by potassium permanganate. The additive is not toxic.

The best thing to do is to call your local water authority to let them know. Once they hear “pink”, they will likely know right away that the cause is potassium permanganate. Until they resolve the problem, avoid using the water on anything that you don’t want to be stained pink. If your water is still pink after resolution, let it run for a little while until it runs clearly.

White (cloudy)

White water is usually caused by bubbles and is totally harmless. It happens often when it is very cold outside, because solubility of air in water increases as water pressure increases and/or water temperature decreases. During the wintertime, water travels from a reservoir (which is really cold) and warms up on the way to the faucet. Bubbles are more prevalent in cold water.  Water from the reservoir also becomes pressureized in disribution pipes, and can hold more bubbles in this state.

You should notice once the water is out of your faucet (and therefore warmer and no longer under pressure), the water will clear up.

Green &  Blue

If you live in a colder climate, you may notice every once in a while that your water or the porcelain in your sink basin is bluish-green. Green water sometimes appears in cooler climates due to copper plumbing corrosion. A copper analysis can be run to determine this cause.

If the water appears more blue than green, this indicates a severe copper plumbing corrision.

Another cause could be the “dezincification” of low-quality bronze alloys that can be found in some valves and water pumps and parts. Test your water for zinc to confirm this.

When the weather is warm, green water could be caused by algae in water supplies that are served by reservoirs or rivers. Algae are not dangerous and can be contained and monitored to prevent an overgrowth significant enough to discolor water. It can also be removed completely if necessary.


The public water supply in the United States is considered very safe, and serious health problems rarely occur. However, if you have any doubt that your water is unsafe to consume, do not use it until the problem at hand is officially resolved. Odor and taste of your tap water are important factors to consider as well. Call your water authority to let them know about any problems.

Posted in: Water Quality

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