Why Is My Well Water Yellow? And Is It Harmful?


Private wells don’t receive the same treatment and monitoring as public water systems, so we have to rely on other methods. A change in the color of our well water indicates the presence of pollutants that need to be removed.

Well water turns yellow, when there is iron bacteria, organic material or ferric iron in the water. Rusty pipes can make the well water appear yellow in our home. Generally, these contaminants aren’t a significant risk to our health in the short term but can cause complications in the long term. 

In this article, we explain what’s turning your well water a yellow tinge, and how to fix it.

Reasons Why Your Well Water Is Yellow

The quality and safety of our well water is up to us. Taking preventive action is always better than reacting after noticing a change in the water, but if your well water has suddenly turned yellow there’s no need to panic.

Odds are you’re dealing with one of these harmless culprits:

Organic Materials

Tannins are byproducts of the natural fermentation from decaying vegetation and can turn well water not only yellow, but also brown. These natural organic materials are picked up as water seeps through peaty or swampy soil on the way to your well’s aquifer.

Tannins don’t present a health risk but give water:

  • A yellow or tea-like color
  • Tangy aftertaste
  • Musty smell

They also produce yellow staining on laundry, porcelain fixtures and dishes.

This type of water pollutant is most common in marshy, low-lying or coastal areas, and generally affects shallow water wells. 

This is an incredibly common problem in the south-east, like Florida and Louisiana.

You can test your water for tannins by filling a glass of water and letting it sit overnight. If the yellow tinge remains the same, then your water is probably contaminated with tannins. If the yellow settles at the bottom then it’s not.

A certified laboratory will be able to confirm the presence of tannins and other contaminants in your well water, and even advise which plant the organic material came from. Depending on the source of your tannins, the best filtration method might vary.

A typical tannin filter works as a water softener, as it traps the contaminants through an anion exchange process. It’s important to clean the filtration system regularly, especially if the water begins to smell like fish.

Tannins can also be removed using an oxidation and filtration method, or with an activated carbon filter.

Rust

One of the most common reasons for faucets to spit yellowish or brown water is rust from our home’s plumbing system, faucets or water heater.

Yellow water is more common in older houses with galvanized pipes as the zinc lining wears off over time.

While rust contamination rarely causes any health issues, a rusty environment can lead to the growth of disease-causing bacteria and mold.

If your yellow water smells like bleach, you should probably hire a professional to conduct some maintenance in your home’s water lines. Installing a filtration system surely helps, but fixing the problem from the source will avoid further damage.

If the discoloration appears in the morning or after not using the faucets for a while and it clears after a few minutes, then you might just have some corroded pipelines.

If the yellow water only comes out of a certain faucet, then you need to replace that specific fixture, or a smaller section of pipe.

When the tint only affects hot water, your water heater is probably to blame. If rust has established inside the unit then unfortunately, it will probably need replacing.

We have more information on identifying sediment in your water heater available here.

Iron

Iron is a common contaminant found in private wells because its in the ground naturally, but there’s more than one type of iron. The iron that doesn’t dissolve in water, and floats as particles is called ferric iron.

When this iron sediment comes in contact with oxygen, it rusts and leaches into the water that comes from your private well. This is one reason why the water can come out red, yellow or orange from the tap. 

There’s no known health risks associated with ferric iron, but it does give your water a metallic taste and, in high levels, even an unpleasant smell.

It can also damage property, causing stains on laundry, dishes, sinks and tubs.

Over time, it accumulates and clogs dishwashers, washing machines, sprinklers, wells, water pumps, and any appliance in contact with the contaminated water.

Again, filling a glass of water and letting it sit overnight is a simple way to test for iron. If the color is stronger at the bottom of the glass, the discoloration is probably caused by this mineral.

Depending on the levels of iron in your private water supply, you can install different types of filters remove it.

An activated carbon filter can effectively remove small amounts of ferric iron. But you’ll need to double up with a second backwashing sediment filter for extra filtration when dealing with significant amounts.

Sequestering, ion exchange, oxidizing filters, and settling are other treatment options. 

You can read more about how reverse osmosis removes iron from water here.

Iron Bacteria

When iron combines with a type of bacteria naturally found in soil and surface water that enters your well, it turns your water yellow and slimy. These small organisms that feed on iron don’t present a direct risk to our health.

But the sludge buildup creates conditions that favor the growth of other organisms that can cause diseases, including, mildew or even E. Coli.

Also, the biofilm it creates can cause clogs in well screens and pipes and reduce your water flow. 

If you notice any of these signs it’s likely because of these bacteria:

  • Unpleasant tastes
  • Odors resembling sewage, petroleum or rotten vegetation
  • Slime buildup in toilet tanks or filters
  • Oily sheen on the water surface,

You can test your water for nitrate and coliform bacteria if you’re worried, and make sure to keep up with your regular maintenance of your well.

Iron bacteria contamination should be handled by a licensed well contractor and requires frequent inspection to keep under control.

Treatments include physical removal, pasteurization and chemical disinfection. Any service done to your well should be handled with care, not placing any equipment on the ground, using only disinfected water and making sure the well casing is watertight and properly capped. 

If your well water smells like rotten eggs we have more information for you available here.

Recent Rain

It is a different story when the yellow discoloration only happens after a heavy rain. In this case, every faucet in your house is spitting yellow water because there is probably surface water leaking into your well. 

There are higher risks involved when drinking yellow water after a heavy rain. Water runoff can carry dangerous elements such as pesticides, fertilizers or animal waste. Rain can also overflow a leaky septic system in the area, threatening to deliver fecal coliform and E. Coli into your home. 

Older wells are more vulnerable to rain damage as seals deteriorate over time, plus they are often shallower than newer wells.

To prevent problems, make sure that any installation, repair or replacement of your well is properly conducted by a reliable professional.

Using Yellow Well Water In The Home

When well water comes out of our taps with a yellow tint, it doesn’t look safe to drink or wash in, but that doesn’t necessarily mean the water isn’t drinkable.

Drinking Yellow Well Water

It’s usually safe to drink yellow well water, although it might have an unpleasant odor and aftertaste. The organic contaminants that turn water yellow are usually not harmful in moderate amounts, but they can provide a favorable environment for the development of other dangerous components. 

We recommend testing your private well water to identify the source of the yellowish tinge and rule out any hazardous pollutants.

Annual advanced testing for contaminants including volatile organic compounds is also best practice, as well as performing a radiological analysis every three to five years. 

Washing In Yellow Well Water

It might seem counterintuitive to wash yourself in yellow water. But the contaminants typically causing this kind of discoloration are readily absorbed by the human body.

It is safe to bathe or shower in yellow well water. However, long term exposure to high mineral content can cause dry skin, hair and scalp, as well as itchiness. Also sediment, rust, tannins and bacteria can damage your faucets, showerhead and bathtub. 

As always, removing the contaminant will improve your water quality, and reduce any risk of damage to your water fixtures.

Russell Singleton

Russell has a Bachelor of Science (Environmental and Marine Geoscience) with Class I Honors. He is currently completing his doctorate in science and is passionate about all earth processes, especially isotope geochemistry and paleohydrology.

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