Pure water has a neutral pH of 7. This means it's neither acidic nor basic. However, the pH of water can vary, typically between 6.5 and 8.5, due to environmental factors and dissolved substances. The pH scale ranges from 0 (highly acidic) to 14 (highly alkaline or basic), with 7 representing the midpoint.
Understanding the pH Scale
The pH scale is logarithmic, meaning each whole number change represents a tenfold difference in acidity or alkalinity. For example, a pH of 6 is ten times more acidic than a pH of 7, and a pH of 5 is ten times more acidic than a pH of 6.
- pH < 7: Acidic
- pH = 7: Neutral
- pH > 7: Alkaline (basic)
Many aquatic organisms thrive within a pH range of 6.5 to 8. The EPA recommends a pH within this range. While the EPA doesn't regulate pH in drinking water (it's considered an aesthetic quality), it's important for water quality and health. Different substances dissolved in water can significantly affect its pH.
Examples of pH in Different Waters
- Rainwater: Slightly acidic (around 5.6) due to dissolved carbon dioxide.
- Pure distilled water: Ideally, a neutral pH of 7.
- Seawater: Slightly alkaline (around 8).
- Drinking water: Ideally between 6.5 and 8.5, although variations are normal.
The pH of water is a crucial indicator of its overall quality and suitability for various purposes, including drinking and supporting aquatic life. Variations from the ideal range can signify potential environmental problems or water contamination.
