How To Remove Tannins From Water? – Best Treatment

Why Should You Learn to Get Rid of Tannis from Water?

Tannins are organic compounds that are found when plants decompose. If your water source is a private well, there’s a high chance that your water contains tannins as tannin can be often found throughout surface water supplies and shallow wells.

Water passing through soil with decomposing vegetation will gather these microscopic tannin particles before entering the well. While low levels of tannins aren’t harmful to humans, they can cause a number of aesthetic problems such as a murky yellow, red, or brown color, musty odor and taste bitter.

Fortunately, there are a number of different methods available on how to remove tannins from water. In our article today, we will be touching on what tannins are, their effects, as well as the different ways to remove tannins from water.

What Are Tannins?

Before we go further, we need to first understand what tannins are. As mentioned earlier, tannins are a type of organic material that’s naturally present in decaying vegetation and plant matter.

This means that you can easily find tannin in earth, leaves, and tree barks. Since they have a browny-yellow color, tannin can stain water, making your white items like laundry and porcelain end up looking yellow.

Another name for tannin is humic acid or fulvic acid and they’re most likely found in low-lying areas, as well as marshy ground and coastal locations. Tannins can seep into surface water sources during rain and also end up in shallow wells.

Are They Harmful to Humans?

Tannins are naturally occurring organic compounds that do not have any serious health effects that you need to worry about. The biggest issue with this small humic acid contaminant is aesthetic-related, like the water’s taste, appearance, and smell. Obviously, nobody would want to wash or drink water that looks dirty, especially when it contains contaminants that are known to cause staining.

There are many reasons why one would want to know how to remove tannins from water. Not only does tannin make your drinking water taste murky or have a tangy taste, the molecules can cause fouling and staining, putting your water-based appliances in risk of permanent damage when exposed to tannin-filled water for extended periods.

How Do Tannins Get Into Your Water Supply?

If you enjoy hiking or simply love the outdoors, chances are that you’ve come across a number of rivers and lakes that are brownish-orange in color. You might have assumed that the color is caused by dirt or other pollutants, but more often than not, the color is simply a result of tannins in the water.

The surface water from rainfall passes over decaying organic matter like leaves, peaty soil, and plant matter, picking up tannins before entering the water body. This is what causes the water to have a brownish red tea-like color. The tiny particles are harmless to human life and can sometimes cause water to take on this color.

Tannin compounds enter well water in the same way. The surface water from rain or snow will seep through peaty soil or fermenting, decaying vegetation, picking up tannins on the way before it reaches your well’s aquifer. This is why your well water may have an amber tone. Those who live in low-lying, marshy or swampy areas, or near the sea are likely to have tannins in their well water.

What Are The Effects?

While tannins are not dangerous to health, they are still a nuisance substance when they’re present in your home.

The biggest issue with tannins is its tea-like color that can act as a dye and can stain laundry and white dinnerware. Tannins in water have been known to stain porcelain fixtures and white laundry, presenting a recurring cleaning problem for homes with tannin issues in their private wells.

Other than the appearance of the water, most would be repelled by cooking or drinking water filled with tannin, regardless of whether they’re natural and safe or not.

It’s completely natural to not want to use murky brownish water and you will end up spending more money on bottled water for you and your family. The money spent on these bottled water can quickly accumulate to a large amount on a monthly basis.

Similarly, washing or bathing in water with tannins isn’t unsafe but it’s definitely far from pleasant since the water will smell or look dirty. Showering or washing clothes with smelly or yellow water may even cause you to be worried about tannin odor lingering on your skin or clothes.

Can I Test for Tannins in My Well Water?

Yes, it’s definitely possible to test and check if you have tannins present in the well water. Doing a water test is also useful before you spend a ton of money on expensive water purifying equipment. All you need to do is to fill up a glass with water and let it sit for several hours (or overnight).

Water with tannin will give off an orange color. However, just because it’s orange, it doesn’t necessarily mean that there are tannins as iron and manganese can result in brownish, orange water too.

One way to distinguish between tannin and iron or manganese is to check where the discoloration occurs. If you have a problem with iron or manganese, the discoloration will settle at the bottom of the glass since iron and manganese molecules are relatively heavier and will sink. On the other hand, if you have tannin, your entire water from top to bottom will have an even orange tone.

Once you’ve established that your water, in fact, does contain tannin, the next step is to check to see the tannin concentration level. Fortunately, there are many state-certified laboratories that you can engage to help you run a water quality check to see how much tannin is in your well water. All you need to do is to collect a sample of your water and mail it to the laboratory.

When running a test to check tannin, the laboratory will usually also recommend testing for additional common well water contaminants, such as iron, hardness minerals, and sulfates. The laboratory will be required to test for iron as this compound can create a “false positive” for tannins.

The laboratories will then have to first test how much iron is present in your water and then subtract this amount from your water’s initial perceived tannins level to get the final actual concentration of tannins.

How to Remove Tannins from Water?

If you’re suffering from tannin problems in your water, fret not as there are a number of different methods and equipment available to help you effectively remove tannins from water. Below are some of the most popular tannin removal methods:

Ion Exchange Water Softeners

Ion exchange process is a popular water softener treatment to effectively remove water hardness minerals like calcium or magnesium with the use of salt. The cation/ion exchange absorption process happening on the resin bed means that the same technology can be applied to treat and remove a high concentration of various other contaminants, including drinking water tannins.

The ion exchange media known as resin, is typically stored in a large tank and the entire system is installed at your home’s point of entry, ensuring clean, soft water is supplied to your entire home.

When using ion exchange systems for tannin removal, the best resin to use is an acrylic or styrene-based chlorine resin. Since tannins have a negative charge, they will be attracted to the ion exchange resin or media in the tank.

Once the ions are exchanged, the anion resin will eventually be saturated with tannins and will need to be regenerated with salt on a regular basis. The regeneration process will help keep the resin bed clean and fresh for optimum tannin removal every time.

The ion exchange water treatment is usually set to undergo regeneration once every two days to prevent organic fouling of the softening resin. Once the system is regenerated, the resin bead is ready for the softening ion exchange process again.

Ion exchange water softeners are not only good at removing tannin, but the water softener can also help homeowners to reduce sulfate present in water. However, it’s worth noting that the anion exchange water softener method may lead to undesired effects on the water such as the pH and chlorine levels in water.

Not only that but once the tannins are exchanged onto the resin, they have a tendency to migrate into the inner matrix of the resin bead. Once this happens, it may be very difficult for the resin to regenerate the tannins out. Hence, frequent regeneration needs to be employed to reduce the likelihood of organic fouling of the resin.

Cleaning Tannin Resin

A possible issue with using ion exchange systems for tannin removal is that the calcium carbonate precipitation can form during the regeneration process as the brine water displacing calcium in the cation resin can increase alkalinity from anion/tannin resin. This precipitate in the resin bed and coating on the drain line can cause a pressure drop through the system during backwash.

Still, calcium carbonate precipitation can be cleaned with a weak acid such as citric or phosphoric acid which will dissolve the precipitation. You’ll need to make sure that the water treatment unit and associated plumbing is compatible with any cleaning agent to prevent further issues.

Soda ash can also be used to help clean ion exchange resin by increasing the pH of the brine, causing the resin to swell to a greater degree. The swelling will make the pores slightly larger to remove tannins that have migrated inside. Tannins are also more soluble at higher pH, producing an even better environment to help strip tannins from the resin.

If soda ash is unsuccessful in cleaning the resin, you can employ chlorine treatment as a last resort. Place approximately 4 to 8 ounces of household bleach into the brine well and activate the regeneration process.

Once you detect a chlorine odor in the drain line, shut the system down for one to two hours. Then continue with the remainder of the regeneration cycle after the system has soaked. You can run a second regeneration cycle to remove any residual chlorine.

However, this cleaning procedure is quite hard on the resin and should only be attempted as a last resort. Strong oxidants, such as chlorine, will attack and break down the ion exchange resin. Currently, there are no ion exchange resins on the market that are resistant to chlorine, only resins that are more tolerant to chlorine.

If this treatment is also unsuccessful, you may need to consider total resin replacement.

Reverse Osmosis System

Reverse osmosis system is an extremely popular water purification method that’s been counted on by many homeowners to help tackle difficult-to-remove impurities from their water source.

Whole house reverse osmosis systems come equipped with a number of water filters (pre-sediment water filter and a carbon filter) and a highly effective reverse osmosis membrane to effectively remove 99.9% of all inorganic and organic contaminants in the water.

Water is set to flow through a pre-filter, carbon filter cartridge, reverse osmosis membranes, and a post-filter cartridge at high pressure, before it passes out of your faucet. The high pressure essentially pushes the small water molecules through the water filters, leaving larger contaminants trapped in the semi-permeable membranes, so only clean water enters your home.

This filtration technology is usually installed at your main water line (at home’s point of entry for whole house filtration or water line beneath kitchen sink for clean drinking water). Since the water is pushed through the reverse osmosis membranes with high pressure, you’ll also benefit from immediate access to clean drinking water once the tap is turned on.

While the reverse osmosis treatment systems are more expensive than other water treatment solutions, they’re designed to effectively treat and trap even the tiniest contaminants – which other water filters are not capable of removing, making them well worth the money. reverse osmosis filters can remove small contaminants thanks to the tiny pores in the reverse osmosis membrane which are only about 0.0001 microns big.

In addition to tannins, reverse osmosis water treatment systems can remove bacteria, chemicals, and fluoride. The membrane filtration can also remove heavy metals like lead and other staining components, such as iron and manganese.


Another alternative to treating tannin in your water is oxidation. You can conduct a simple jar test to determine the tannin concentration and retention time you’ll need to remove tannins.

There are also different kinds of oxidants available in the market that can help you effectively reduce tannin levels and improve overall water quality. The most common oxidant is chlorine. However, the issue with chlorine is that the chemical may react with your water’s tannin compound and produce a carcinogen called trihalomethane.

Another oxidant to consider is activated carbon units which are also known to be able to help lower tannins in water to acceptable levels. It is recommended for you to consult your carbon manufacturer to get the right type of carbon product.

Frequently Asked Questions for Tannin Removal

How to remove tannins from water with activated carbon filters?

Yes, activated carbon filters are a good choice for removing natural compounds such as tannins and for improving overall water quality. The technology behind using activated carbon as a filtration process is known as adsorption, which causes the contaminants in the water to stick to the surface of the filter media while the water passes through.

Just like many other water filters, activated carbon filters have a limited capacity with a life ranging from 6 months to 2 years.

However, the only issue with using activated carbon to remove tannins is that they aren’t as effective as other methods. Activated carbon is more popular for helping to remove chlorine and lead instead, which is why activated carbon filters are best combined with another type of filter such as a reverse osmosis membrane or oxidation system.

In fact, an activated carbon filter is usually included as one of the many stages in RO filtration. So, if you’re interested in using activated carbon filtration for tannins removal, you may be better off investing in an RO ultrafiltration system instead.

Is it possible to avoid tannins in my water?

Since tannin compounds are naturally occurring in most surface water supplies, it’s quite difficult to avoid tannins in your water. In fact, avoiding tannins may be way more hassle than it’s worth. It’s simply a lot easier to remove tannins from your water with water filter systems or ion exchange resins than trying to prevent them.

Shallow wells are more likely to contain high tannin content. So, if you’re planning to build a well for your home, make sure to build it deep enough to avoid tannins for surface water. You also need to make sure that your wells are well-built without any cracks or holes that will allow tannin particles to flow through.

Is it important to test a well for tannins?

Yes, it is recommended to run a water test to check what is present in your water before deciding on which water treatment method to get. It’s not just important to check for tannins, but you should also check for other contaminants like bacteria, iron, manganese and sulfur. By knowing what’s in your water, you’ll have an easier time picking the right systems for the job.

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