Understanding Water pH
Water’s pH is a measure of its acidity or alkalinity, ranging on a scale from 0 to 14. A pH value of 7 indicates a neutral solution, like pure water.
Solutions with a pH below 7 are considered acidic. Conversely, solutions with a pH above 7 are alkaline (basic). The pH scale is logarithmic, meaning each whole pH value change represents a tenfold difference in acidity or alkalinity.
The Recommended pH Range for Drinking Water
The recommended pH range for drinking water is 6.5 to 8.5. While the human body effectively regulates its internal pH, extreme deviations in drinking water pH can contribute to other issues.
Water with very low or very high pH can affect plumbing systems. Acidic water, with a pH below 6.5, can corrode pipes and fixtures, potentially leading to the leaching of metals like lead and copper. Conversely, too alkaline water, with a pH above 8.5, can cause scale buildup within pipes and appliances, reducing their efficiency and lifespan.
Beyond infrastructure concerns, pH levels also influence the aesthetic qualities of drinking water. Water that is significantly acidic might have a metallic or sour taste. Conversely, highly alkaline water can taste bitter or soapy.
The U.S. Environmental Protection Agency (EPA) Secondary Drinking Water Standards suggest a pH range of 6.5 to 8.5, primarily for aesthetic reasons related to taste and the prevention of pipe corrosion and scaling. These standards are not health-based but focus on the overall quality of the water.
Measuring and Adjusting Water pH
Homeowners can assess their water’s pH using several methods. Simple pH test strips provide a quick, approximate reading by changing color when dipped in water. Liquid test kits offer a similar color-matching approach, often providing a slightly more precise result. For the most accurate measurements, digital pH meters are available, which provide a numerical reading of the water’s pH.
If water pH falls outside the desired range, various methods can be employed for adjustment. To increase the pH of acidic water, acid-neutralizing filters are commonly used. These filters typically contain media such as calcite (calcium carbonate) or magnesium oxide, which dissolve into the water and raise its pH.
For more significant adjustments to acidic water, a soda ash (sodium carbonate) injection system can introduce an alkaline solution into the water supply. Conversely, if water is too alkaline, acid injection systems can lower the pH, though these are less common for residential applications. Aeration, a process that exposes water to air, can sometimes slightly reduce pH by allowing dissolved carbon dioxide to escape. For substantial or whole-house pH adjustments, consulting water quality professionals is advisable to ensure appropriate and safe solutions.