Why Is My Water Yellow?


Sometimes changes in tap water are impossible for us to see. Other times they are impossible to miss. One of the easiest changes to spot is tinted water. So, have you noticed your tap water turn yellow? It may not smell bad, yet it certainly raises some questions. Fear not and read on – because we have some answers.

Reasons & Solutions For Yellow Tap Water

Let’s start with the good news. Most of the time, yellow water does not pose a significant health risk. Still, it's worth investigating. To address the problem, it’s helpful to answer a couple of questions first:

  1. Is your water is coming from (a) a public water system or (b) a private well?

  2. Is your water (a) always yellow or does it (b) return to normal after running for a few minutes?

If you can answer these two questions, our guidelines below can help you diagnose why your water is yellow and what you can do about it.

1a. My Water Is Yellow – And My Water Is Treated By A Water Utility (Public Water System)

Your water utility is performing repairs

Every water distribution system needs to be repaired from time to time. Utility repair work upstream might be the culprit for yellow tap water, as rust and other materials may enter to into your water supply during maintenance work. It’s best to call your water supplier to confirm that this is the cause.

Your water utility is “flushing” the water lines

In order to clear out stagnant areas of your system, water suppliers must occasionally increase the water pressure in your pipes and water mains. During this “flushing”, it is common for yellowish rust in the pipes to loosen. As a result, your water quality may change. However, it should only be temporary. You will know that “flushing” is the cause of your colorful water when only your cold water is affected.

1b. My Water Is Yellow – And I Have A Private Well

Iron Bacteria

Iron bacteria are small organisms which naturally occur in soil and water. They are not known to cause disease, but can tint your water. This occurs when these bacteria combine iron and manganese with oxygen to form a yellowish, slimy buildup.

What can you do about iron bacteria? Check out of our Tap Score Iron-Oxidizing Bacteria Test – it’s a great diagnostic tool to detect if iron-related bacteria is affecting your pipes.

Organic Material

Byproducts of nature's fermentation process, tannins are created as water passes through peaty soil and decaying vegetation. They are one of the most common causes of water coloration. While they do not pose a health risk, tannins can turn your water yellow. The best way to remedy this type of coloration is to treat your water with:

  • Activated Carbon Filters
  • Anion exchange
  • Chlorin ation and subsequent filtration

Build Up of Iron and Manganese

Iron (Fe) and manganese (Mn) are common in groundwater supplies and often occur together. Elevated levels of either do not pose any known adverse health risks. In fact, both are regularly required by your body as mineral nutrients to stay healthy. However, they do have less than desirable effects on your water color.

Their presence in water may be in multiple forms. When the water comes from the tap with a yellow tint, the Fe and Mn have combined with organic matter and is called colloidal. While difficult to remove, it can be treated. Treatment options include sequestering, ion exchange, oxidizing filters, and oxidation and filtration or settling.

2a. My Water Is Yellow – Always

If your run your tap water for an extended period of time and the color does not clear up, it is likely that the issue caused by a disturbance of pipeline sediments in the water main. These disturbances occur when dissolved iron is stirred up in naturally-occurring sediments that exist in all water systems. In this case, the best thing to do is to contact your water authority and drink bottled water until the yellow-ish color subsides. Alternatively, you can have a strong home filter installed.

2b. My Water is Yellow–But Returns to Normal After a Few Minutes

If the color clears after a few minutes, the issue is most likely in your house plumbing. Old pipes tend to accumulate rust, which in turn can leach into your water. The best fix? Replace your rusted pipes.

So, what’s the takeaway?

Yellow tinted water can come from a variety of causes and most of the time, it does not mean that your water is unsafe. Still, you should always investigate changes in your water quality. Once you’ve identified what’s causing the yellow color, choose an appropriate water filter. EWG’s Updated Water Filter Buying Guide can help. If you drink water from a private well, we recommend that you test your water every three years to find out what’s in your water.