The pH of drinking water is a measure of its acidity or alkalinity, ranging from 0 to 14. A pH of 7 is considered neutral, while values below 7 are acidic and values above 7 are alkaline. The pH scale is logarithmic, meaning a single unit change represents a tenfold change in acidity or alkalinity. While pure water is neutral, most drinking water has a pH influenced by its source, geology, and treatment processes. A balanced pH is crucial not just for taste, but also for preventing corrosive or scaling effects on plumbing and for ensuring effective disinfection.
The Recommended Range for Safe Drinking Water
For most public water systems, and for optimal health and aesthetic quality, a pH range of 6.5 to 8.5 is widely recommended by organizations like the EPA and WHO. This range is not a strict health guideline in itself, as the human body is very efficient at regulating its own blood pH. Instead, it's a practical standard used to minimize problems within water distribution systems and ensure palatability. For instance, water that is too acidic (below 6.5) can be corrosive, leaching metals like lead and copper from pipes. Conversely, water that is too alkaline can cause scaling and encrustation in plumbing.
When High pH Becomes a Concern
While drinking water with a pH slightly above 8.5 is generally not a direct health risk, excessively high levels introduce notable concerns. These concerns are not related to the trendy, moderately alkaline bottled waters (pH 8-9), but rather to significantly higher levels that can occur naturally or through certain treatment processes.
Aesthetic and Household Issues
- Unpleasant Taste and Feel: Water with a pH greater than 8.5 can develop an unpleasant, bitter, or soapy taste.
- Plumbing Damage: High pH water is often associated with hard water, which can lead to scaling or mineral buildup inside pipes and appliances. This buildup can reduce water flow, decrease the efficiency of water heaters, and ultimately cause damage.
Direct Health Risks of Extremely High pH
- Hyperkalemia: For individuals with impaired kidney function, drinking water with a pH above 9.8 can be especially risky. Extremely alkaline water has been linked to hyperkalemia, or dangerously high blood potassium levels, in some clinical studies.
- Gastrointestinal and Irritation: Consuming water with a pH higher than 10 can potentially lead to gastrointestinal irritation in sensitive individuals. In rare cases, extremely high pH (above 11) can cause skin, eye, and mucous membrane irritation.
- Nutrient Absorption: Regularly consuming very high-pH water can potentially neutralize stomach acid, which could impair the absorption of essential minerals and vitamins. This is a particular risk for those with low stomach acid or those taking proton pump inhibitor medications.
Factors Contributing to High Water pH
Several factors can cause water to have a high pH:
- Geological Sources: Water that passes through limestone and other alkaline rock formations naturally picks up minerals like calcium and magnesium, increasing its pH.
- Water Treatment: Chemicals such as lime or soda ash are sometimes added during municipal water treatment to balance pH and minimize pipe corrosion.
- Industrial Discharge: Agricultural runoff and industrial waste can contain chemicals that raise water's pH.
- Algae Growth: In surface water sources like lakes and ponds, algae absorb carbon dioxide during photosynthesis, which can cause the water's pH to rise during daylight hours.
A Comparison of Water pH Levels
| pH Level | Description | Potential Effects on Water Quality and Health |
|---|---|---|
| < 6.5 | Acidic | Corrosive to plumbing, metallic or sour taste, can leach heavy metals from pipes. |
| 6.5 - 8.5 | Ideal/Neutral to Slightly Alkaline | Palatable, generally safe, minimizes pipe corrosion and scaling. |
| > 8.5 | Moderately Alkaline | Bitter or soapy taste, potential for scale buildup on pipes and appliances. |
| > 9.8 | Highly Alkaline | Potential for hyperkalemia in sensitive individuals (especially with kidney disease) and other irritation. |
Conclusion: Prioritizing Water Safety Over Trends
When considering the pH of your drinking water, it is important to distinguish between safe, recommended levels and unproven marketing claims. The human body has natural mechanisms to maintain a stable pH balance, making the consumption of slightly alkaline water largely irrelevant for most healthy individuals. The real health risks lie at the extremes of the pH scale. The best approach is to ensure your water comes from a safe, regulated source that adheres to established guidelines, such as the EPA’s recommended range of 6.5 to 8.5. If you have concerns about your water's pH or quality, a professional water test is the most reliable way to gain clarity. Remember, prioritizing proper hydration with clean, safe water is far more beneficial than chasing a specific pH value. For more information on drinking water standards, visit the EPA Drinking Water Regulations website.
