Yellow or Tea-Like
A yellow to yellow/brownish tinge in the water and staining on fixtures and laundry are usually caused by tannins. Tannins are a natural organic matter that can result from nature's fermentation process as water passes through peaty soil and decaying vegetation. In fact, tannins are responsible for the brown color in coffees and teas. They appear primarily in river or surface water and swamps, but, often find their way into wells through cracks and fissures in rock formations. While tannins are not harmful to health, they do present a number of other problems in our water. Tannins are carbon based, which is significant because carbon tends to deplete oxygen. This lack of free oxygen in tannin-filled waters can contribute to the problem of acid water and can prevent iron from oxidizing, thereby rendering iron removal filters and water softeners ineffective. More than 0.5ppm (parts per million) of tannin can be troublesome when trying to remove iron from water.
Anion exchange resins are often used for tannin removal; but the resin is sensitive to hardness, so most of these systems include a water softener as a pretreatment. Oxidation and filtration can also be used to remove tannins, but anion exchange and softening is a much simpler method. Some types of activated carbon filters may also reduce tannins to acceptable levels. A water quality professional in your area can assist with treatment.