Understanding the pH scale and purified water
The pH scale is a measure of how acidic or alkaline a substance is, with a range from 0 to 14. A value of 7 is neutral, like pure water, while anything below 7 is acidic and anything above is alkaline. The reason Aquafina is often on the acidic side of neutral is due to its production method. Unlike spring water, which often contains natural minerals that contribute to a more neutral or alkaline pH, Aquafina is sourced from public water supplies.
The brand then purifies this water using a proprietary seven-step process called Hydro-7, which prominently features reverse osmosis (RO). This extensive filtration strips out not only impurities and contaminants but also most of the natural minerals, or Total Dissolved Solids (TDS), like calcium and magnesium. When these buffering minerals are removed, the water becomes more susceptible to absorbing carbon dioxide from the atmosphere, which creates a weak carbonic acid and lowers the water's pH. This is why purified and distilled waters, including Aquafina, often have a pH below 7.
The Hydro-7 purification process
The Hydro-7 process is designed to remove a wide range of dissolved solids and organic compounds to ensure consistent purity and taste. The key steps include:
- Prefiltration: Initial filters remove larger particles.
- Activated Carbon Filtration: Removes chlorine and other organic compounds that affect taste and odor.
- Reverse Osmosis: Uses semi-permeable membranes to filter out up to 98% of TDS, including salts and other minerals.
- Polishing Filters: Removes any remaining particles.
- Ultraviolet (UV) Sterilization: Further sanitizes the water.
- Ozonation: A final sterilization step using ozone gas before bottling.
This rigorous process results in a very low TDS count, which is a hallmark of purified water, but also explains the slightly acidic pH. While some brands reintroduce a controlled blend of minerals for taste and a more balanced pH, Aquafina's process focuses primarily on purification to achieve its consistent, clean taste.
Aquafina vs. other bottled water brands: A comparison
To better understand Aquafina's pH, it's helpful to compare it to other popular bottled water types. The following table contrasts Aquafina with various other brands and water types based on typical pH ranges and purification methods.
| Brand/Water Type | Source | Purification Process | Typical pH Range | Notes |
|---|---|---|---|---|
| Aquafina | Public water source | Reverse Osmosis, Ozone | 5.5–7.0 | Purified water, typically slightly acidic. |
| Dasani | Public water source | Reverse Osmosis | 5.0–6.0 | Also purified, with added minerals for taste, yet still acidic. |
| Fiji | Artesian Aquifer | Natural filtration | 7.5–8.0 | Naturally sourced from volcanic rock, contains minerals. |
| Essentia | Purified water | Microfiltration, Electrolytes | 8.5–9.5 | Enhanced with electrolytes for an alkaline boost. |
| Poland Spring | Natural Spring | Filtration, Ozonation | 7.0–7.5 | Sourced from natural springs, contains some minerals. |
| Tap Water | Municipal Supply | Filtration, Chlorination | 6.5–8.5 | pH is regulated and can vary by location. |
Is slightly acidic water harmful?
The slightly acidic nature of purified water like Aquafina is generally not considered harmful for consumption for most people. The human body maintains its own pH balance, and the small amount of acidity from drinking water is easily neutralized by the body's internal systems. Concerns mainly arise from repeated, long-term exposure, particularly regarding dental health. Frequent or prolonged sipping of low-pH beverages can potentially contribute to enamel erosion over time, especially if other factors are present.
- For dental health: Dentists often warn that a pH below 5.5 can lead to enamel demineralization. While Aquafina's pH is often above this threshold, some dental professionals suggest minimizing prolonged sipping of low-pH beverages. Rinsing with neutral water or drinking alongside meals can help.
- For overall health: For most healthy individuals, the body's natural buffering capacity is more than sufficient to handle the minor acidity of purified water. The larger health benefits of proper hydration far outweigh the minimal concerns over the pH of purified water.
Conclusion: Making an informed choice
The pH of Aquafina water is typically between 5.5 and 7, making it slightly acidic due to its rigorous reverse osmosis purification process. This is not unusual for highly purified or distilled water, where natural buffering minerals have been removed. While the minor acidity poses no significant health risk for the majority of people, those concerned about dental health may want to be mindful of their consumption habits.
Ultimately, the choice of bottled water depends on personal preference and dietary considerations. For those seeking a neutral or alkaline beverage, options like certain spring waters or enhanced alkaline waters are available. However, for a consistently pure and clean-tasting water, Aquafina remains a popular choice, with a purification process that directly influences its final pH.
For more in-depth information on the pH of various beverages and its effect on dental health, consult resources from a reputable dental association, such as the American Dental Association.
