Why Is My Water Yellow?

Reviewed by: James Layton
Updated on:
February 21, 2024

Key Takeaways

Contaminants Responsible for Turning Water Yellow

Sometimes both private wells and city water supply can get mixed up with unwanted contaminants from various sources that give your water an off-putting appearance.

Luckily, most of the causes can be solved by installing a water treatment system in your home. First, test your water to find out exactly what impurities are present, yellow or not. Then, consult our list of the best whole-house water filters to find one that suits your home’s exact cocktail of contaminants.

The most likely contaminants turning your tap water yellow are iron, manganese, and tannins. 

Iron and manganese

Excessive iron in the water supply gives it a brownish tint that some may perceive as yellow. Three types of iron particles can be found in water — ferrous, ferric, and bacterial. 

Ferrous iron

Ferrous iron, also called “clear iron,” is the dissolved form of iron in the water. It is colorless and invisible to the naked eye. In high enough amounts, ferrous can give your drinking water a metallic taste. It’s also responsible for staining laundry, sinks, and fixtures.

Ferric iron 

When ferrous iron reacts with oxygen, it’s oxidized into solid particles of ferric iron, also called rust.

These new particles are insoluble, and if they’re small enough to be suspended in the water, you may notice a tint, i.e., yellow water.

Bacterial iron 

Some species of bacteria feed off clear iron and produce insoluble particle iron. These bacteria can form a sticky and gooey substance in the well, and in extreme cases, you’ll see it in your water.

You can pretty much notice it with the naked eye, but there is no research suggesting that iron bacteria can cause health issues. They’re just a nuisance.

However, if iron-producing bacteria are getting into your well, they’re getting in there somehow. That means other, more harmful bacteria could be getting into your well.

You should have your water tested to be certain no water-borne pathogens are tainting your drinking water.

If you do end up testing positive for any type of bacteria or other pathogen, you should have your well (and your septic tank, for that matter) evaluated and repaired.

You also may want to enlist the help of a UV purifier to make your well water safe for drinking.

Here’s a list of the industry’s best UV purifiers to get you started.

Manganese

Manganese and iron originate from the same sources, so they are mostly present together in your water. Manganese in its soluble state is colorless, but it can convert into particles after reacting with oxygen in the water and produce a tint ranging from yellow to dark brown.

Tannins

Tannins refer to a group of organic compounds that are present as “polyphenols” in plants, fruits, and vegetation. (The puckery taste in unripe fruits is caused by this substance.)

Tannins enter the groundwater as a result of the decomposition of leaves, bark, and other parts of plants. It’s mostly found in peaty and marshy grounds filled with decaying vegetation.

An excessive amount of tannins in water turns it yellow like an iced tea and gives it a marshy taste. The shade of yellow in this case is much lighter as opposed to that of iron contamination, but it’s still enough to put you off.

In some places, the shade is closer to dark red, brown, and black due to different concentrations of dissolved compounds.

Tannins mostly affect private wells. City treatment plants remove tannins before chlorination because when organic matter reacts with chlorine, it can produce carcinogens known as trihalomethanes.

For more information about tannins, see our how-to guide for removing tannins from water.

Other Reasons Behind Yellow Water

There are plenty of ways your water supply can get contaminated with color-changing pollutants. Not only should you test your tap water regularly for iron, tannins, and everything else under the sun, but you should also look out for other potential causes, such as rusty pipes and old water heaters.

Let’s discuss some of the other reasons that may be lurking behind the yellow color of your tap water.

Rusty pipes 

If the pipeline connected to your house is old, it’s more susceptible to corrosion than if it were new. Old things degrade (except anyone called Aunt Betty, for some reason. Aunt Betty lives forever).

Pipes are made from a combination of iron, zinc, and copper that can oxidize by reacting with oxygen in the water. The process is called corrosion, and it can release large particles that break away and enter the passing water.

In old homes without aerators on the faucets or a whole-house filter, you may see this when you first turn on your water. However, if your water is tinted as a result of this, there will be other signs that your pipes are corroding. For example, your water-using appliances would break down from the resulting clogs. You may also notice leaks throughout the property.

It’s super unlikely this explains your issue, but if it does, yellow water is the least of your problems.

Scale buildup 

Some areas have hard water containing minerals, such as calcium and magnesium, that form scale in your pipes, faucets, and fixtures over time. There’s a high chance that iron in your water supply combines with these minerals to build up in showerheads, taps, and faucets.

Tap water running through such scale buildup catches an orangish hue and creates yellow tap water.

To confirm if your yellow water is due to scale buildup, turn your cold water tap on and let it run for 20–30 minutes. If your water clears up after a few minutes, you probably have built-up scale inside your taps. If it doesn’t, the problem lies somewhere else.

You can easily clean the scale buildup by removing the faucet heads and scrubbing them with vinegar and a regular soap. To prevent scale buildup in the future, you’ll want to install a water softener in your home.

Here’s a list of the best water softeners.

Groundwater contamination

The majority of the freshwater we use in our daily lives comes from aquifers under the ground. But these water sources can get polluted easily.

Some external factors, like construction, industry, and agriculture, can disrupt the system and invite pollutants in the water stream. Other times, activities like mining and disposal of industrial chemicals can increase contaminants in groundwater.

This is more likely to be a problem with well water, which undergoes no treatment before reaching your taps.

However, treated city water can become polluted after treatment on the way to your taps due to cracked and contaminated pipes. Sometimes city water treatment plants change the groundwater source without prior notification, which can also cause water to change color. 

Water discoloration can also happen from the routine testing of fire hydrants by the local authorities. The high water pressure in the supply lines breaks off built-up iron sediment and turns your tap water yellow.

In such a case, run your taps for a few minutes and the water will get clear again. If the issue persists, you must contact the relevant local authorities to discuss a solution. 

How to Fix Yellow Water

Fixing your yellow water will depend on if the source is coming from the polluted groundwater or municipal water, a faulty water heater, or rusty, old pipes.

1. Get your water tested. 

Now that you know what contaminants can make your clear water yellow and through what ways they can seep into your water, you need an official diagnosis. Simply looking at your water is not enough to identify why it’s got a yellowish look to it.

To fix your yellow water problem, you need to establish the source.

The best way to know exactly what impurities you need to treat is to send a sample of your water off to a proper laboratory. We partner with Tap Score because we know it’s a trustworthy and accredited lab that will return an accurate result of your water quality. You, too, can trust Tap Score with this task.

Set up a Tap Score water test today and get on track to clean up your yellow water with the right water treatment.

2. Install a water treatment system.

Installing a purification system is the best route to take if your water gets contaminated often due to external factors. Even if you get your water from a municipal treatment plant, it can still contain certain pollutants you might not want to consume, such as chlorine. 

A filtration system is excellent for removing sediment and pollutants that can turn your water yellow. But there isn’t a one-size-fits-all water filter, contrary to popular belief. 

Here are a few water treatment technologies that you’ll have to choose from when you shop for the right system for your home:

Air-injection oxidation filter

An oxidation filter is probably the most efficient filtration system for removing iron, sulfur, and manganese from well water. It’s made from contemporary technology that uniquely removes contaminants by oxidizing them into particles that are filtered out through mechanical filtration. 

Oxidation is most often done with air, but some popular systems use chlorine, which is also an oxidizer. Most use air, though.

Here’s how it works: Untreated water passes through an air bubble. The air oxidizes iron and other metallic ions into solid particles that are eventually captured by the following filter medium, usually activated carbon or greensand. Later the polluted filter is flushed with water to remove solid particles in the process called backwashing.

These units typically cost between $200 and $1,000.

Ultrafiltration membrane 

Another viable option is an ultrafiltration membrane system, which uses hydrostatic energy to force water through the filters. As a result, heavy molecular particles are trapped in the system while low-molecular-weight solute passes through the filter.

Ultrafiltration can capture pathogens, pyrogens, bacteria, and tannins. However, they aren’t suited to remove iron and manganese. Iron and manganese can actually clog and ruin the fine membrane.

Ultrafiltration systems are extremely pricey and can cost you anywhere from $1,500 to $10,000. 

Activated carbon filters

Activated carbon filters are made from natural materials like coal or coconut shells. Activated carbon is one of the most effective treatments for a wide range of contaminants, including tannins. As such, it can remove tannins and other organic contamination, as well as iron and manganese.

A whole-house activated carbon filter can cost from a few hundred dollars to a few thousand. Read our collection of the best whole-house carbon filters for more information.

Water chlorination

You can also use chlorine bleach to disinfect your well with a process called shock chlorination. It’s an inexpensive and simple one-time disinfection of your well. Shock chlorination is a suitable treatment for iron bacteria, but it’s not a long-term solution. It doesn’t guarantee the bacteria won’t come back.

It also doesn’t work for tannins, ferric or ferrous iron, or manganese.

Some people use bleach to chlorinate the water, which is fine and does the trick. However, chlorine tablets specifically made for disinfection have a higher concentration of chlorine dioxide and are more effective than ordinary bleach.

Make sure to not use water for 24 hours after pouring chlorine into the water well. See our article How to Clean Well Water for more about shock chlorination.

Shock chlorination can cost less than $100, but, again, it’s only suitable for a one-time treatment of iron bacteria.

Reverse osmosis system

Reverse osmosis is another workhorse of modern filtration. It can remove up to 99% of contaminants, including lead, copper, arsenic, chromium, fluoride, and forever chemicals (PFAS).

However, it has a little more difficulty removing certain VOCs and pesticides, as well as hydrogen sulfide.

Reverse osmosis is most common at the point of use, such as a dedicated faucet in the kitchen, but they do come in whole-house versions. Most people think that’s overkill, though.

Here are some of the best whole-house reverse osmosis systems.

3. Replace or repair.

If it’s the water heater, all you need to do is replace your sacrificial anode. No big deal.

If the problem is bacteria, have a professional assess the health of your well casing, the placement of your well cap, and the structural integrity of your septic tank.

However, if the problem is corroding pipes, that is a big deal. You’ll need to hire a plumber to assess the situation.

Is Yellow Water Safe for Consumption?

It largely depends on the concentration of iron and tannins in your water. 

The US EPA has not set any strict limits for iron and tannins in water because they are essentially harmless to the body. However, the secondary maximum contaminant limit (SCML) for iron is 0.3 mg/L, after which it starts changing the color and taste of water.

Let’s assume your water is affected by iron and tannins and has turned an appalling yellowish shade. Here’s what you should do:

  • If the color is of a lighter yellow shade, it’s safe to drink and cook food in it until the problem is fixed. 

  • If the water has dark yellow or orange shade, it probably contains high amounts of iron or tannins. You may want to avoid drinking it, and you’ll definitely want to avoid washing your laundry in such water because it can leave yellow stains all over your clothes. 

  • If your water tests indicate the presence of high amounts of iron bacteria and tannic acid, it’s best to stop consuming it in any form and immediately switch to bottled water.

How to Prevent Water from Turning Yellow?

Because the most likely causes of yellow water are iron, manganese, and tannins, there’s really no “prevention” for this problem.

Iron, manganese, and tannins are naturally occurring and if you live in an area with high levels of either, you could get yellow water.

Learn more about the quality and mineral makeup of the groundwater where you’re located. Swampy and marshy grounds have higher chances of tannin contamination. For example, states in New England, the southwest, and the northwest are more prone to these contaminants. 

Research filters and water treatment methods that suit your budget and needs to effectively banish all kinds of pollutants in your water.

Final Thoughts

When water turns yellow, it’s usually not cause for alarm. Water can turn yellow due to the presence of either iron, iron bacteria, manganese, tannins, or a combination. Other causes might have to do with the condition of your pipes and water heater.

Be sure to get your yellow water tested in an accredited lab. Once you identify the reason for your yellow water, it’ll be easier to fix the issue that’s turning your water into an unappetizing yellow cocktail.

The Drinking Water team is committed to helping you achieve clean and healthy water from every tap in your home. That’s why we consult with experts in the field, such as our on-staff consultant, James Layton.

With James’ expert feedback and our own extensive research and testing methodology, we’ve compiled a wealth of material to educate and inform you about water quality, water treatment, and other topics related to drinking water.

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