The U.S. Environmental Protection Agency (EPA) recommends a pH range of 6.5 to 8.5 for drinking water. While pure water has a neutral pH of 7, the EPA considers pH an "aesthetic" quality, not a primary health concern, meaning it doesn't have strict regulations on it. However, this recommended range ensures the water is palatable and doesn't corrode plumbing.
Understanding pH in Drinking Water
pH measures how acidic or alkaline (basic) a substance is. A pH of 7 is neutral. Numbers below 7 indicate acidity, and numbers above 7 indicate alkalinity.
- Slightly acidic water (pH 6.5-7): This is generally safe and common.
- Neutral water (pH 7): Pure water has a pH of 7.
- Slightly alkaline water (pH 7-8.5): Also generally safe and acceptable.
While some companies promote alkaline water's health benefits, scientific evidence supporting these claims is limited. The acidity of your stomach renders any pH changes from drinking water negligible.
Sources of Variation in pH Levels
The pH of drinking water can vary based on several factors:
- Source of water: Surface water (rivers, lakes) typically has a pH between 6.5 and 8.5, while groundwater might range from 6.0 to 8.5.
- Treatment processes: Water treatment methods can affect pH.
- Minerals and other substances: Dissolved minerals and other substances in the water can influence pH.
- Bottled water: Bottled water pH varies from around 6.5 to 7.5, with "alkaline" waters having higher pH values.
Important Note: pH and Water Safety
While the EPA doesn't strictly regulate pH for health reasons, it's a factor in overall water quality. Extremely high or low pH levels can indicate other potential contaminants and may affect the taste and corrosiveness of water. Always rely on your local water authority for information about your specific water quality.
