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What Are Tannins In Water? (Help!)

Is your water getting light yellowish-brown with an earthy taste? It can be tannins!

Tannins are a type of organic compound that arise from the fermentation of vegetation. Tannins are commonly observed in groundwater sources in low-lying regions, such as marshes, swamps, and coastal areas. 

They aren’t dangerous but can stain on fabrics and laundry, so you would want to remove them.

Continue reading to know everything about tannins in water. 

🔍Are Tannins In Water Harmful?

Are tannins in water harmful

No, tannins in water aren’t harmful. Hence, EPA (Environmental Protection Agency) doesn’t classify them as primary contaminants. 

However, tannins in water can cause aesthetic effects such as:

  • Discoloration: Tannins can cause water to appear tea-like yellowish-brown tint, discouraging you from drinking.
  • Taste and odor: Tannins can impart a musty odor and earthy taste to the water, making it less palatable for consumption. These sensory changes are due to the organic nature of the tannin molecules interacting with other compounds in the water.
  • Staining: Water tannins can cause stains on plumbing fixtures, laundry, and surfaces it comes in contact with. These stains can be difficult to remove and require additional cleaning efforts or specialized cleaning agents.

Although tannins from water are not harmful bacteria, they can create conditions that favor bacterial growth or indirectly impact water quality, leading to potential health risks.

Some ill effects related to the presence of bacteria in tannin-rich water include:

  • Biofilm formation: Tannins can contribute to the formation of biofilms on surfaces in contact with water, such as pipes and plumbing fixtures. Biofilms are slimy layers that provide a protective environment for bacteria to grow and thrive, potentially leading to an increased risk of bacterial contamination in drinking water.
  • Interference with disinfection: Water tannins can react with disinfectants like chlorine, reducing their effectiveness in killing bacteria. This interaction can lead to insufficient disinfection, allowing harmful bacteria to survive and pose a risk to human health.
  • Pathogenic bacteria: If untreated or improperly treated tannin-rich water becomes contaminated with pathogenic bacteria, such as E. coli or Salmonella, it can cause serious health issues, including gastrointestinal illnesses, fever, and dehydration. These bacterial infections can be hazardous for vulnerable populations like infants, seniors, and individuals with compromised immune systems.

🤔What Causes Tannin In Water?

What causes tannin in water

The best way to understand how tannin occurs in water is to recall how we make tea. First, we take a cup of clean water. As we add tea leaves or dip a tea bag, the water color changes to brown or black.

More specifically, tannins in water can be caused due to the following:

  • Surface Runoff and Soil Seepage: Tannins are released into water sources through two primary mechanisms: decomposing plant materials and agricultural runoff. When leaves, bark, and wood decompose, tannins leach into the soil and eventually enter groundwater or surface water systems. 

Additionally, rainwater runoff from agricultural fields and orchards carries tannins from decomposing organic materials in the soil, including peaty soil, into nearby streams, rivers, and lakes.

This process contributes to an increased amount of tannins in surface water supplies, making proper treatment and filtration methods essential for treating tannins from water and maintaining water quality.

  • Wetland environments: Wetlands, such as swamps and marshes, contain a high concentration of decaying plant materials. The slow water movement in these ecosystems allows tannins to dissolve into the water, leading to higher concentrations of tannins in wetland areas.
  • Industrial processes and waste: Industries that use tannin-rich materials, like paper manufacturing and leather tanning, may release tannins into water bodies through their wastewater. If this wastewater is not treated correctly, it can increase tannin levels in water sources. 
  • Forest fires can cause large amounts of plant materials to break down rapidly, releasing tannins into the environment. Subsequent rainfall can wash these tannins into nearby water bodies, causing a temporary increase in level of tannin.
Also Read: Why I Have Brown Sludge In Water Softener Tank?

🤷How Do I Get Rid of Tannins in My Well Water? (Tannin Removal Steps)

How do i get rid of tannins in my well water

Surface water supplies, like lakes and rivers, can be naturally rich in tannins due to surrounding vegetation and runoff. Proper water treatment systems and filters are essential for maintaining water quality and reducing the potential risks of tannin-rich water.

However, before removing tannins from your well water, confirming their presence and distinguishing them from iron is essential. 

💡Did you know?

One tell-tale test is to fill a clear glass with water and let it sit undisturbed for several hours. If the water turns yellow or brown and the color does not settle at the bottom of the clear glass, it’s likely due to tannins. For a comprehensive evaluation, consider using Tapscore’s Yellow Tap Water Test.

Once you’ve confirmed the presence of different tannins in your water, you can explore the following methods to remove them:

  • Tannin Softener System: Tannin water softener uses ion exchange resin to target tannins. As water passes through the resin bed, tannins are attracted to the resin and exchanged for sodium ions. The system periodically regenerates the resin using a salt solution. By incorporating a water softener into the process, you can effectively remove tannins and hardness-causing minerals from your water supply.
  •  Reverse Osmosis: Reverse osmosis (RO) systems use a semi-permeable membrane to separate tannins and other contaminants from water. Water is forced through the membrane, leaving tannins and impurities behind.
  • Ultrafiltration: Ultrafiltration uses a membrane with smaller pores than reverse osmosis, allowing water to pass through while retaining water tannins and larger molecules. This method effectively removes tannins without significantly altering the mineral content of the water.
  • Activated Carbon Filters: Activated carbon filters can adsorb and remove tannins and other organic compounds via water treatment. The large surface area of activated carbon attracts tannins, trapping them within the filter. Activated carbon filters are typically used with other treatment methods to ensure the complete removal of tannins and other contaminants.
  • Oxidation: It involves adding chemical oxidants like chlorine or ozone, which can break down tannins into more minor, less problematic compounds. Filtration methods like activated carbon or sediment filters more easily remove these broken-down molecules.

💁🏻‍♂️Tannins In Water: FAQs

What does tannin do to your body?

From a water quality standpoint, tannins in drinking water do not pose any significant health risks. 

However, tannins in food can lead to adverse health effects such as blood coagulation and hypotension. Tannins have been found to have various physiological impacts, including the acceleration of blood clotting, reduction of blood pressure, decrease in serum lipid levels, induction of liver necrosis, and modulation of immune responses.

Will a carbon filter remove tannins?

Activated carbon filters can effectively adsorb and remove tannins from water; however, they are typically used with other water treatment methods to remove tannins and other contaminants.

How to test for tannins in well water?

Here’s how to test for tannins in well water: 

1. Fill a transparent glass with water.
2. Let it lie overnight.

If the color sinks to the bottom of the glass, it’s iron and manganese in water and not tannin. 

If the color’s intensity is unaltered, tannins are most likely to blame. 

You can also use DIY test kits that involve color-changing reagents or send a water sample to a certified laboratory for more accurate analysis. 

What is an acceptable level of tannins in drinking water?

Tannin is not currently classified as a primary contaminant by the EPA. Therefore there is no established data on acceptable levels for this substance. However, it may result in aesthetic issues like staining and discoloration, so you might use RO or carbon filters to remove it.

Is it safe to swim in water with tannins?

Swimming in water with tannins is generally safe, as tannins are non-toxic to the skin. However, high concentrations of tannins in your water may cause water discoloration and reduced visibility, which can concern some swimmers.

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