Tannins in Well Water, and Why Well Water Testing is Important

Does your drinking water come from a well? If that’s the case (and your home doesn’t have a reliable water filtration system), you will most likely encounter various water contamination problems. We’re talking about issues ranging from hard water and high iron content to strong sulfur odors and tannins. Wait, tannins? The compounds that produce the astringent or bitter taste in wine, unripe fruits, dark chocolate, and other foods and beverages? Yes, that’s correct.

As it turns out, tannins are also found in well water. They are generally considered unpleasant in water and are, therefore, known water contaminants. If you spend enough time outdoors, you may see a lake or river with yellow, brown, or amber-colored water. While this color is often mistaken for dirt or iron contamination, it usually indicates the presence of tannins.

Unfortunately, tannins can make their way into your tap water, mostly if your home’s water source is a shallow well located in a swampy or coastal area. But how can tannins get into your home’s tap water in the first place? More importantly, how do you know if they are present in your well water system?  Read on as we uncover the facts.

Also note that if you do have tannins then our whole house well water filter will not work as it will foul the media. We’re working on developing a system to address tannins.

What are Tannins in water?

Without getting too scientific, tannins are a group of natural organic plant materials, possibly a byproduct of fermentation or water passing through decaying vegetation or swampy soil. Think of a teabag. When the water is added to the cup and passes through the tea leaves inside the teabag, the tannin molecules dissolve and change the water’s color to green, black, golden-brown, or peach. In the same way, water passing through peaty soil or over leaves, branches, and other vegetation in lakes, streams, rivers, and aquifers causes the water to absorb the tannins and become discolored. But how can they end up in your home’s water supply?

How do Tannins get into my home’s water supply?

As we mentioned above, tannins are commonly found in rivers, lakes, and other surface waters. When leaves, grasses, pine needles, and other organic matter fall into these water sources, the plant matter breaks down over time and remains in the water. Therefore, if your city gets its water from a surface water supply that contains high levels of tannins, there’s a good chance those tannins will end up in your tap water. Plus, since the United States Environmental Protection Agency (EPA) does not regulate tannins in water, it’s easier for them to pass through local water systems to your home. The compounds can also leach into groundwater wells that draw water from surface waters containing high tannin levels and seep underground and enter private well water through cracks in the well’s wall.

Are Tannins in water harmful?

Thankfully, tannins are more of a nuisance than a health hazard in drinking water. Most of the problems homeowners face with the compounds are aesthetic issues, making the water unpalatable to drink and staining household items.

Besides giving your drinking water a bitter, tangy, or tart aftertaste and a musty or earthy odor, there are a few issues associated with tannins:

  • Tannins may create a light yellow or dark brown tint in the water. (This tea-like color works similar to dye and can cause permanent stains on fabrics, fixtures, china, and laundry in your home.)
  • Tannins can affect water clarity and are easily oxidized. Thus, they’re likely to affect standard disinfection methods, like UV and chlorination.
  • They may bind with iron in water, making them harder to remove.
  • Water containing tannins may be a haven for bacteria.

Furthermore, tannins tend to bind up minerals in the water, softening it, lowering the pH, hardness, and alkalinity. That means if you use tannin-contaminated water to fill your aquariums, the water’s acidity could stress fish that cannot thrive under such conditions.

Tannins can also pose severe water problems by reacting with chlorine in the water to form new compounds called disinfection byproducts (in this case, trichloromethane, a suspected carcinogen). Tannins can even interfere with the equipment used to treat other water problems. For example, the resins or media in iron filters, cation exchange filters, and neutralizing filters can become coated by the tannins and may no longer work properly.

On top of that, tannins in water could indicate surface water intrusion, and hence, the presence of other types of potentially dangerous contaminants. Surface water can reach a drilled well because the casing seal is separated from the bedrock, a vein has opened up, or from a leak in the casing pipe. It can also occur depending on the local geography.

When natural organic materials from the ground seep down cracks in the bedrock and get into the well, they may impart a skunk cabbage or pig manure type of smell. And since tannins can travel easily from surface water to your groundwater source, chances are it’s also easy for pathogens and other contaminants to do the same.

So, if you are testing your water for tannins, we recommend testing for bacteria, iron, alkalinity, sulfates, total dissolved solids (TDS), and hardness as well. These tests may help determine what treatment method(s) will be most effective for your situation.

How do I know if I have tannins in my well water?

It’s impossible to tell if your well water contains tannins by observing it with your naked eye, or smelling or tasting it. That’s because water contaminated with iron or manganese looks almost identical to tannic water.

The best way to confirm if tannins are in your well water is to order a Watercheck Testing Kit. The standard Watercheck test kit from the National Testing Laboratories, Ltd. is designed for homeowners whose drinking water comes from a private well or spring.

This water testing package contains everything you need to identify irregularities in your well water. It will test your water for 75 or more common contaminants, including:

  • Tannins
  • VOCs (including TCE, MTBE, and PCE)
  • Inorganic chemicals (including nitrates and fluoride)
  • Heavy metals (including iron, arsenic, uranium, and mercury)
  • Bacteria (the presence or absence of Total Coliform and E. Coli)
  • Trihalomethanes (THMs)
  • Physical characteristics (including Total Dissolved Solids (TDS), hardness, turbidity, and pH)

We recommend the Watercheck Pesticide option for even more thorough testing, as it is a complete version of the standard kit, adding 2o pesticides, herbicides, polychlorinated biphenyls (PCBs). This Pesticide kit also comes from the National Testing Laboratories, Ltd., one of the industry’s most recognized laboratories.

If you’re ready to take the guesswork out of your well water quality, simply order the testing kit, mail them the sample, and receive your in-depth report within days. Testing your water has never been easier!

The Importance of Testing Your Well Water Regularly

As you probably know, the EPA regulates most public water systems. That means local water systems are required to filter and treat their water before distributing it to consumers. The problem is that the EPA does not regulate private water sources (like private wells). Because of this, the well owners are responsible for ensuring their well water is safe to use. Considering that, it is vital that well water testing is done before the water is used for any purpose. Why? Because regularly testing your well’s water quality is crucial in maintaining a safe and reliable drinking water source.

Regular testing helps you to:

  • Learn about the quality of your water and identify existing contamination problems
  • Address the issues at hand to ensure the water is suitable for the intended use, especially if used for drinking by humans and animals
  • Protect your well water from every potential cause of contamination
  • Track changes in quality over time
  • Determine the effectiveness of a given treatment system

Please note that the quality of any water source may change over time, even suddenly. And sometimes, these changes can go unnoticed as the water may look, smell, and taste the same. Thankfully, testing your water will help you spot and address water contamination problems early, which could otherwise worsen and affect your health and household.

Final Thoughts

If your drinking water looks like tea or Coke or smells earthy, it may be time to get your well tested for tannins. A reliable water test can reveal eye-opening details about your well water quality. For example, there may have been toxic contaminants in your water all along, putting you and your family’s health at risk. At the moment SpringWell Water does not offer any solutions to remove tannins from your water although we’re working on it. We do not recommend our whole house well water filter as the tannins will foul the media inside and the system will stop working over time.