BLUE GREEN STAINING FROM LOW pH WATER
BLUE / GREEN STAINING & CORROSION CAUSED BY LOW pH
Water pH level reflects how acidic or alkaline it is. pH stands for “potential of hydrogen,” referring to the amount of hydrogen found in a substance (in this case, water). pH is measured on a scale that runs from 0 to 14. Seven is considered neutral, meaning there is a balance between acid and alkalinity. A measurement below 7 means acid is present and a measurement above 7 is basic (or alkaline). Low pH is a common phenomenon in New England’s water supply.
Acidic water can leach metals from pipes and fixtures, such as copper, lead and zinc. It can also damage metal pipes and cause aesthetic problems, such as a metallic or sour taste, laundry staining or blue green staining (from dissolved copper) in sinks and drains . You may even experience “pin-hole” leaks in your piping system which will lead to the potential need for costly replacement. Water with a low pH may contain other metals in addition to the before-mentioned copper, lead and zinc.
The U.S. Environmental Protection Agency (EPA) does not regulate the pH level in drinking water. It is classified as a secondary drinking water contaminant whose impact is considered aesthetic, even though the results of water with a low pH can be devastating to the water quality once it reaches a home or other end user point. However, the EPA recommends that public water systems maintain pH levels of between 6.5 and 8.5, which is a good guide for individual well owners, however, symptoms as previously described are an indicator that corrective action may be necessary. You may very well see staining and other issues with water toward the lower or higher end of this range which should be addressed.
HIGH pH OR ALKALINE WATER
Drinking water with a pH level above 8.5 indicates the presence of a high level of alkalinity. High alkalinity does not pose a health risk, but can cause aesthetic problems such as an alkali taste to the water that makes coffee taste bitter, scale build-up in plumbing, and lowered efficiency of electric water heaters. Highly mineralized alkaline waters also cause excessive drying of the skin as they tend to remove normal skin oils.
WATER TREATMENT FOR LOW pH
Two methods for adjusting pH are acid neutralizing, point of entry filters (black tank with control head on left) and chemical feed pump systems (large tank on right side of photo) injecting a neutralizing solution.
The most common solution is an acid neutralizing filter using calcite or ground limestone (calcium carbonate) for pH correction, but could also include a blend of magnesium oxide and calcite if the pH is very low ( black Tank with control head at left). The affect is kind of like a giant food-grade “Tums” slowly releasing into the water to neutralize the acid. Since the water absorbs these minerals when it passes through the filter, the alkalinity and hardness will increase. Hardness is easily treated with a water softener that uses an ion exchange process to remove the hardness minerals. The result of this two-step process is neutral pH with softened water.
For well water with extremely low pH, a chemical feed pump solution may be required. This is made with well water and soda ash (similar to baking soda) and mixed in a solution tank. The chemical feed pump injects this high pH solution into the household piping system where it reacts with the low pH water in a retention tank (typically 40 gallons) and neutralizes the pH. Neutralizing with soda ash slightly increases the sodium content of the water which may pose additional health concerns if someone in your household is on a reduced sodium diet. This can be addressed with a reverse osmosis drinking water system which desalinates and purifies water to a very high degree.
Your water treatment professional, after analyzing your initial water test results, will be able to make a determination as to the best approach for you.
For more on water pH, see the link at Low pH link.