Why is My Water Yellow?

By: Jake Gallagher | September 26, 2023

Imagine it’s Monday morning and you get up feeling groggy, already unmotivated to go to work. Next thing you know, the showerhead is pouring gross yellow water all over your body. Super annoyed—and not a little grossed out—you scream in frustration: Why is my water yellow?!

If you’ve found yourself in a similar situation, don’t worry, you’re not alone. Yellow water is a common occurrence among both private-well owners and city-water folks. It’s mainly caused by iron and tannins found underground. 

I’ve outlined the probable reasons behind this awful yellowish tinge in tap water and the solutions to tackle the situation based on comprehensive research and years of experience with household water systems.

Let’s get into it!

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. The ones majorly responsible for turning your tap water yellow are iron and tannins. 

Iron and manganese

Excessive iron in the water supply gives it a yellowish or brownish tint. Three types of iron particles are responsible for polluted 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. Ferrous gives your drinking water an unpleasing metallic taste. It’s also responsible for staining laundry, sinks, and fixtures.

Ferric iron 

When ferrous iron comes in contact with air, it readily reacts with oxygen particles. Oxidation converts once innocent iron particles into “ferric oxyhydroxide (FeHO₂),” also called rust. This new flaky compound is highly soluble and gives a dreadful yellowish hue to the water—hence, yellow water. It also gives tap water a metallic, rusty smell and taste that can discourage you from drinking it.

Some other contaminants that come with iron are manganese, lead, and copper. Ferric iron combined with manganese turns water into a dark yellow color. The presence of these contaminants largely depends on the water quality in your region.

Bacterial iron 

Some species of bacteria feed off the iron and severely pollute the water. For example, bacterial iron forms a sticky and gooey substance in water and turns it orange or yellow.

You can pretty much notice it with the naked eye. It happens due to poor cleaning of the supply line and irregular maintenance. There is no research suggesting that iron bacteria can cause health issues. However, this type of bacteria can create an environment for other, potentially fatal bacteria to grow in pipes and water-storage tanks, so in these cases, you may want to drink bottled water until you sort the issue out.


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 black and brown flakes after reacting with oxygen in the water. 

This metallic compound gives your water a dense black and brown shade which can sometimes appear as yellow and orange, depending on the concentration levels.


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. And 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 make you disgusted.

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

Tannins can affect both private wells and city supply lines. Moreover, treatment plants aren’t explicitly designed to remove tannins from water. It’s an organic molecule, and the likelihood of it reaching an aquifer is relatively high. 

Tannin molecules aren’t much of a threat, but some experts say that when rainwater passes through local runoff, it can carry toxic bacteria along with tannins. Now, bacterias are dangerous and must be treated as soon as possible.

Other Reasons Behind Yellow Water Supply

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 and tannins but also look out for other potential causes, such as rusty pipes and old water heaters. Let’s discuss some of the other reasons behind the yellow color of your tap water.

Rusty pipelines 

It may very well be possible that the pipeline connected to your house is old, making it susceptible to corrosion. 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 forms a thick, crusty, orange coating inside pipes that breaks away and enters the passing water.

If you’re having trouble figuring out whether your well or city water is the problem or if it’s your dirty plumbing system that’s causing yellow water, ask your neighbors about their tap water quality. This will give you a good idea about the scope of the problem.

Scale buildup on faucets 

Some areas have hard water with dozens of unwanted minerals that form scale in your faucets 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 a nasty orange 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.

Faulty water heater 

Sometimes the problem is a neglected water heater. Your hot water tank has a relatively large amount of dissolved ionic solids, which can become a catalyst for redox reactions. These reactions initiate corrosion on the metal surface and form rusty sediments that settle at the bottom of your tank. Most water heaters have a “sacrificial anode” that restricts corrosion until it expires. But sometimes it fails and traces of rust end up in your hot water. 

To see if this is the case, turn on the hot water and let it run. If yellow water only comes through the hot water supply, your water heater needs some cleaning and maintenance. 

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 or relocation of the supply line, can disrupt the system and invite pollutants in the water stream. Other times, activities like mining and disposal of industrial chemicals can increase the amount of iron in groundwater. This is more likely to be a problem with well water, which undergoes no treatment before reaching your taps.

Treated city water can catch pollutants 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 sediments 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. 

Is Yellow Water Safe for Consumption?

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

The US EPA (Environmental Protection Agency) 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 until the problem is fixed. 
  • If the water has dark yellow or orange shade, it probably contains high amounts of iron or tannins. Avoid drinking it and washing your laundry in such water, as 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.

Get Your Tap Water Tested 

Now that you know what contaminants can make your clear water yellow and through what ways they can seep into your water, here are a few ways to identify them.

Visual test 

Let’s start with the simplest one. Fill a clear glass with yellow tap water and let it sit for six hours. The ferrous molecules will eventually oxidize by reacting with the atmosphere and turn into flaky particles that settle down at the bottom of the glass. This test will help you identify ferrous and ferric iron in water but won’t clarify the presence of bacterial iron or tannins. 

DIY testing kit

The next one involves a little more effort on your part. Get one of the easily accessible DIY water-testing kits online or from your local home improvement store. There are many affordable testing kits available that can easily detect 0–300 mg/L (or PPM) of tannin molecules. 

You can also buy a general water testing kit for as low as $150 that can detect a wide range of pollutants, such as sulfur, iron, arsenic, and nitrates.

Talk to experts 

Still confused? Having your water sample tested by an accredited laboratory is the best way to go. I said “accredited” because many laboratories offer water-testing services, but their results can’t be trusted at face value. 

Thankfully, the EPA gives a complete guide to water testing. You can find a certified lab near your area using this link

Testing prices vary with the number of contaminants you want the test for. Typically, the price range lies between $100 and $700. 

Call the lab beforehand and ask them for the details about sample preparation. Labs usually take a week to return the results. Once you know the exact concentration of iron or tannin molecules, it will be easy for you to opt for the right solution to your yellow water problem. 

Experts recommend testing both private well water and city water once every six months, even if it’s visibly clear, because many contaminants can lurk in your water silently and only lab tests can identify them.

How to Fix Yellow Tap Water

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 treatment plant, it can still contain some pollutants that might enter the water through broken pipes or incomplete water treatment. 

Make sure you purchase a water-cleaning system from a brand that is registered by EPA and WQA. Registration just means that the companies are made to follow certain health and safety protocols during manufacturing. Note that the product itself is NOT certified by the EPA or WQA because these organizations don’t certify or test the cleaning units. So don’t fall for false advertisements that claim products have been certified by a renowned organization, and be vigilant about your purchase. 

Install a water purification system 

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

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 precipitates that are filtered out through mechanical filtration. 

In this process, raw water passes through the air and filter medium. Air oxidizes iron and other metallic ions into solid precipitates that are eventually captured by the filter medium. 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 an organic membrane to capture pathogens, pyrogens, bacteria, and our main target, tannins. However, they aren’t suited to remove rust. For that, an effective water softener works best in tandem with an ultrafiltration membrane.

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

Activated-carbon filters 

Activated carbon filters are a good choice for removing tannins and iron particles. Moreover, you can enhance its effectiveness by installing an ultraviolet (UV) light system before it, which can kill pathogens and iron bacteria. The average price of activated carbon filters is $500.

Water softeners 

A water softener is a hard-water treatment system that can also remove up to 5 mg/L of ferrous iron from water. Water softeners use an ion-exchange system to replace charged metallic contaminants with harmless ions, which is why it doesn’t have any effect on organic compounds with no charge—like tannins. 

A water softener’s iron removal capacity is lower than oxidation and reverse-osmosis systems. It can cost you as low as $200 and as high as $6,000.

Water chlorination

Shock chlorination is a cheaper alternative where the whole plumbing system is flushed with chlorine or hydrogen peroxide. This effectively kills iron bacteria and other harmful microorganisms residing in your pipeline and well.

Although chlorination is a cheap process and won’t cost you more than $150, it’s inefficient and may cause rust to reemerge after some time. Also, chlorine can react with tannin molecules and create trihalomethane—a cancer-causing agent that can show up in the water supply.

Reverse-osmosis system

A heavy-duty reverse-osmosis (RO) system is your best bet if you’re willing to jack up your budget a little. These water treatment systems can target numerous bacteria, pathogens, iron, tannins, zinc, calcium, and magnesium very efficiently. If the water in your area is muddy and sedimented, I suggest you add a sediment-filter before your RO system. It’ll prevent inconvenient clogging and make your RO membrane last longer. 

RO systems are available within the price range of $250–$4,000.

Replace rusty pipeline

In case the rusty supply lines are the cause of your yellow water, you must call your maintenance guy and get your well and plumbing system cleaned or replaced. 

Unfortunately, there isn’t any cost-effective way of dealing with rust in an old plumbing system. 

If you’re thinking of DIYing, of course, you can just grab a brush and start scratching the insides of your pipes, but it’s very inefficient and tedious. Also, it’s extremely dangerous as things can easily go south and clog your pipes and other equipment. It’s better to contact an expert plumber.

If the rust originates from a rusty water heater, then simply replace the corroded sacrificial anode and flush the pipeline afterward. 

How to Prevent Water from Turning Yellow?

Prevention is better than cure. And prevention can save you a lot of money, effort, and time. 

Even if you have removed the source of iron and tannins in your water—for example by replacing rusty pipes—there is no guarantee that yellow water won’t show up again. Here are a few things you should do to stay clear of dirty contaminants in your water: 

  • Schedule regular maintenance of your pipelines and water system. 
  • Don’t let sediments accumulate and harden in your pipes and faucets for a long time. 
  • Make sure you test your water every six months.
  • 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. 
  • Finding filters and treatment methods that suit your budget and needs can effectively banish all kinds of pollutants in your water.

Final Thoughts

When water turns yellow, brown, or straw-colored, it’s usually not cause for alarm. Water turns yellow due to the presence of either iron or tannins or a combination of both. 

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. Start by inspecting the condition of your supply pipes and replacing the rusty old ones if necessary.

If that’s not the case and the problem starts with the water supply, then you can use oxidation filters, reverse-osmosis systems, or water softeners to treat your water.