Fact Sheet: pH


Brief Overview:
Contaminant: pH
Category:  Inorganic
MCL: Acceptable Range: 6.5 to 8.5
Source: Naturally alkaline or acidic ground water
Effect: Causes corrosive water, stains
Followup: Treat, retest for pH, and Lead, Copper, Cadmium
Treatment: pH Neutralizer


Natural waters used as a drinking water source may range from highly alkaline to very acidic. Most natural waters fall in the range of 5 to 8. Certain areas lacking limestone are notorious for having low pH (acidic water). Typically, waters with a low pH are very low in hardness and are considered naturally soft.


The pH scale goes from 0 to 14, with a pH of 7 considered neutral. Water with a pH below 7 is considered acid, and water with a pH above 7 is considered alkaline. The EPA considers pH to be a secondary contaminant, with an acceptable range of 6.5 to 8.5. This is a non-enforceable standard set primarily for aesthetic reasons rather than health-related reasons. PH is not directly a health hazard. However, high and low pH levels can cause elevated levels of unwanted toxic metals by dissolving them from the plumbing system. If you see bluish-green stains on the tub or sink of a home using copper water pipes, acidic water is corroding the metal parts of the plumbing system. If a home has brass water faucets, or copper tubing whose solder contains lead, high levels of lead may be found when water stands in the pipes overnight. High and low pH can cause also an unpleasant taste, and shorten the life span of copper tubing.


If non-corrosive, approved plastic piping is used in the home, low pH requires no particular follow up. However, if copper tubing is used, the pH should be adjusted to the desired level. Then, retest for pH, lead, copper, and cadmium (first draw and flushed samples should be taken).


If non-corrosive, approved plastic piping is used in the home, no treatment is required. If copper tubing is used, the most commonly installed treatment equipment is a pH neutralizer to adjust the pH to the desired level of 6.5 to 8.5. Adjustment of pH is accomplished by addition of alkaline or acidic chemicals such as sodium hydroxide, lime, soda ash, carbon dioxide and sulfuric acid.