What is Tannin in Water?

Have you ever turned on your bathtub and the water is yellow.  It looks gross.  You think to yourself my water is rusty.  Is it or could it be tannin in the water?  Tannins are not a common  in our region, but there are specific areas where we’ve found tannin in the water.What are tannins?

Tannins can be found in peaty soil from vegetation decay breakdown.  They are a natural and organic matter in nature.  When they are in water, they give a tea-like, faint yellow, color.  Tannins will even cause an unpleasant after taste when drinking water.  They will occasionally leave a yellow staining in fabrics, fixtures, and laundry.  When smelled, tannins have a musty, earthy odor.  When filling a bathtub with water, the bathwater will have a yellow tint and look dirty.

How do I know if I have tannin in my water?

A quick at-home test is to fill a glass of water and let it sit overnight.  If the color settles to the bottom, then the discoloration is likely from iron and/or manganese in the water.  If the color intensity remains the same, then it is likely tannin in your home’s water.

If you feel you have tannins, the most reliable way to confirm tannins are in your water is to have an independent testing lab test your water.  It is advised to contact your local water professional to find the nearest certified testing laboratory.

Are tannins harmful to humans?

No, tannins are only an aesthetic concern even though they make the water look dirty and unappealing.

How do I remove tannins from my water?

When a home’s water has tannin, it is recommended to us anion resin to remove the tannin.  The anion resin is used in conjunction with a water softener using cation resin.   Since the anion resin is sensitive to hardness, it is best to soften the water with a water softener. The combination system will used salt, sodium chloride, and citric acid as its regenerant to soften the water and remove tannins.