Blue / Green stains indicate the presence of Copper in the water. Water picks up Copper from natural deposits, industrial processes, wood preservatives, and plumbing. A potential health effect from ingesting water with excess Copper is gastrointestinal irritation. Alan’s Insights : Most of the blue/green stains we see are caused by the water leeching the copper from the pipes in the home. This can happen because the pH of the water is too low (or too acidic), the water contains a chemical such as ammonia or chloramines that simply dissolve the copper, the water is under the influence of an electrical charge which causes electrolysis which decomposes the copper or other metal, excess dissolved oxygen in the water which reacts with carbon dioxide to release copper ions into the water, or excessive water movement such as may be found with a hot water re-circulation pump which literally wears the copper pipe out by the forces of friction. Contrary to what we often hear, this is not the result of having a water softener. Some people believe a water softener makes the water aggressive. However, anyone who understands how a water softener works knows this cannot be the case. A water softener works using ion exchange which means it swaps one type of ion for another type of ion. This action leaves the water the same balance it was before. The reason this old tale lives on is most likely that the softened water does not create scale in the pipe any longer. This may even allow the scale that had previously formed to wear away, thereby exposing the pipe to the corrosive nature of the water that existed all along but only being noticed by the homeowner after the installation of the water softener. There are very effective solutions available for this type of situation. You should consult with a licensed water treatment professional to find the best solution for your particular problem. That way you can be sure to make it better and not worse. Especially with something like this you need someone with knowledge of the chemistry and not just someone with something to sell. For help with this problem call us at 512-756-7710 or email us at [email protected] Alan’s insights are observations made by Alan over decades of experience but are in no way intended to diagnose a specific problem. Every water system challenge is unique in it’s own way and a licensed professional should always be consulted before applying any treatment option.