What is pH and why does it matter for water?
pH measures the acidity or alkalinity of a substance on a scale from 0 to 14, with 7 being neutral. Acidic substances are below 7, while alkaline substances are above 7. The scale is logarithmic, meaning each unit change is tenfold. While pH is an indicator of water quality, the value itself is rarely a direct health risk to humans. It affects taste, odor, and the potential for pipe corrosion and contamination. Highly acidic water (below 6.5) can corrode pipes, releasing metals like lead and copper. The WHO and EPA recommend an aesthetic pH range of 6.5 to 8.5 for drinking water.
The human body and pH balance
Your body maintains its blood pH within a narrow range of 7.35 to 7.45. The idea that alkaline water neutralizes body acidity lacks scientific evidence. When water enters the stomach, it mixes with acidic gastric juices (pH 1.5-3.5), neutralizing its original pH. The kidneys and lungs are the primary regulators of the body's pH.
Is water with a pH of 7 considered healthy?
Drinking water with a pH of 7 is safe and healthy. Pure water is naturally at this neutral point. While tap water often varies slightly due to minerals, neutral pH water offers benefits:
- Optimal Hydration: Effectively hydrates without altering the body's natural balance.
- No Adverse Effects: A pH of 7 has no immediate or long-term negative health impacts.
- Neutral Flavor Profile: Generally offers a clean, palatable taste.
Comparing neutral (pH 7) to acidic and alkaline water
| Feature | Neutral Water (pH 7) | Acidic Water (<6.5 pH) | Alkaline Water (>8.5 pH) |
|---|---|---|---|
| Effect on Health | Safe and healthy; no direct health impact | Safe on its own, but can leach heavy metals from pipes | Generally safe, but can taste bitter or cause issues with disinfection |
| Taste | Clean and neutral | Metallic or bitter taste due to mineral corrosion | Slippery feel or soda-like taste |
| Plumbing Impact | Generally benign for plumbing | Highly corrosive, can damage pipes and leach metals | Can cause scale buildup on pipes and fixtures |
| Source Example | Pure, distilled water | Rainwater or water from granite areas | Hard water from limestone-rich areas |
| Scientific Support | Widely recognized as safe | Potential health risks from heavy metal leaching | Health benefit claims are largely unproven |
Why water pH fluctuates
Water pH can deviate from 7 due to:
- Dissolved Minerals: Passing through mineral-rich rocks (like limestone) makes water more alkaline or "hard".
- Atmospheric Gases: Water absorbs carbon dioxide from the air, forming carbonic acid and slightly lowering pH.
- Acid Rain: Pollution leads to acid rain, lowering the pH of water sources.
- Decomposition: Decaying plants release acidic compounds.
- Water Treatment: Facilities adjust pH for disinfection and corrosion control.
The takeaway on drinking neutral water
Drinking water with a pH of 7 is safe and represents the natural state of pure water. The human body handles minor pH variations effectively. The main pH-related safety concern is the potential for acidic water to corrode pipes and introduce heavy metals. Ensuring your water is free of contaminants is more important than focusing on a neutral pH.
For more detailed information on water quality standards and parameters, consult the World Health Organization's Guidelines for Drinking-water Quality.
Conclusion: A balanced pH is a healthy standard
Water with a neutral pH of 7 is completely safe to drink. Regulatory bodies focus on a safe range (typically 6.5–8.5) and prioritize contaminant testing over aesthetic pH quality. Claims of significant health benefits from alkaline water are not scientifically supported, and the body's systems manage internal pH regardless of water source. Ensuring your water is contaminant-free is the most crucial aspect for health.
