Understanding the pH Scale and Purified Water
The pH scale is a fundamental concept in chemistry, measuring how acidic or alkaline a substance is. The scale ranges from 0 to 14, with a pH of 7 considered perfectly neutral. A value below 7 indicates acidity, while a value above 7 signifies alkalinity. For reference, lemon juice is highly acidic (pH 2-3), while baking soda is alkaline (pH ~9). While pure water theoretically has a neutral pH of 7, real-world conditions mean this is rarely the case for drinking water.
Water can become more acidic or alkaline depending on its source and the purification processes it undergoes. For consumers, understanding the pH of bottled water can be important for various reasons, including taste preference, potential impact on dental health, or simply satisfying curiosity about what they are drinking.
The Typical pH of Great Value Purified Water
Independent testing has shed light on the specific pH of Great Value's purified water. In a 2023 dental office study, Great Value purified water was measured at a pH of 6.20. Another water quality test conducted in late 2024 revealed a similar pH of 6.04 for the "Purified Water with Minerals" variant. These figures indicate that Great Value purified water is consistently slightly acidic. It is important to distinguish this product from the brand's alkaline water, which is treated to have a much higher pH, typically 9.5 or more. The slight acidity of the standard purified version is not an accident but a direct result of its purification method.
The Purification Process and Its Effect on pH
The slightly acidic nature of many purified waters is a direct consequence of the reverse osmosis (RO) purification process. Here's how it works:
- Removal of Minerals: RO uses a semipermeable membrane to filter out contaminants and impurities, including dissolved minerals like calcium and magnesium. These minerals normally act as buffering agents, which help water resist changes in its pH. With these buffers removed, the water becomes more susceptible to pH fluctuations.
- Absorption of Carbon Dioxide: Once purified, the water is exposed to the air. The carbon dioxide ($CO_2$) in the atmosphere readily dissolves into the water, forming a weak carbonic acid ($H_2CO_3$). This process is what lowers the pH, pushing it into the slightly acidic range. This effect is not limited to bottled water; even rainwater naturally has a slightly acidic pH for the same reason.
The minimal amount of minerals left in purified water also impacts its taste, which some describe as 'flat'. While Great Value adds some minerals back for taste, they are not enough to bring the pH back to a neutral 7, nor are they intended to provide the same mineral content as natural spring water. The process is primarily focused on removing impurities to meet purification standards.
Great Value Water: Purified vs. Spring vs. Alkaline
To better understand the pH of Great Value's offerings, here is a comparison of their different bottled water types:
| Feature | Great Value Purified Water | Great Value Spring Water | Great Value Hydrate Alkaline Water |
|---|---|---|---|
| Typical pH | ~6.0–6.2 | ~6.9 | 9.5 or higher |
| Acidity Level | Slightly acidic | Nearly neutral | Alkaline (basic) |
| Purification Method | Reverse Osmosis | Natural filtration (from spring) | Reverse Osmosis with minerals/electrolytes added back |
| Mineral Content | Very low (some added for taste) | Natural mineral content from source | Electrolytes added for taste and alkalinity |
| Taste Profile | Generally considered 'clean' or 'flat' | Varies based on mineral content | Smoother taste due to added minerals |
Health Considerations of Water pH
For most healthy individuals, drinking water with a pH level between 6.5 and 8.5 is generally considered safe and poses no health risks. The human body has a remarkable ability to regulate its internal pH balance, and the stomach's highly acidic environment (pH 1.5–3.5) effectively neutralizes the small amount of acidity from water. Therefore, the slightly acidic pH of Great Value purified water is not a cause for concern regarding overall health.
However, some specific factors are worth noting:
- Dental Health: Highly acidic beverages over time can be corrosive to tooth enamel. While a pH of ~6 is far less acidic than soda (pH ~2.5), it is more acidic than a neutral pH. Swishing water with a higher pH, like the brand's alkaline option, can help restore a healthy oral pH balance after consuming acidic foods.
- Mineral Intake: Purified water lacks the naturally occurring minerals found in spring water, such as calcium and magnesium, which are important for bodily functions. A balanced diet is necessary to ensure these essential minerals are still consumed, as purified water cannot serve as a significant source.
- Kidney Health: While purified water is generally fine for the kidneys, individuals with specific health conditions should consult a doctor about their water intake needs.
Conclusion
In summary, the pH of Great Value purified water is typically slightly acidic, with test results indicating a range around 6.0–6.2. This slight acidity is a natural byproduct of the reverse osmosis purification process, which removes mineral buffers, and the subsequent absorption of atmospheric carbon dioxide. For the average consumer, this pH level poses no health concerns, as the human body's pH regulation system is highly effective. However, those interested in higher-pH water can opt for Great Value's alkaline product, which is specifically formulated for that purpose. The choice between purified, spring, or alkaline water ultimately comes down to personal taste preference and individual health considerations, but all are safe drinking options.
For further reading on the EPA's standards and guidelines for drinking water quality, you can visit their website.
Additional Considerations for Water Purity
While pH is a notable characteristic, it is not the sole indicator of water purity. The purification process for Great Value water effectively removes a wide range of impurities, contaminants, and chemicals. However, even with rigorous purification, some products may contain trace byproducts from the disinfection process. These levels are often well below regulatory limits but are a reminder that no water is 100% pure $H_2O$. Factors like the original source water and subsequent handling can all influence the final product. For those with compromised immune systems, purified water provides a reliable and safe hydration source, especially when the quality of local tap water is questionable. The key is to choose the water that best fits your needs, whether that's the minimal mineral content of purified water, the natural mineral balance of spring water, or the higher pH of alkaline options.
The Importance of Water Testing
Occasional testing by independent labs provides valuable transparency into the actual contents of bottled water. These reports often detail not only pH but also mineral content and potential disinfection byproducts. For consumers, these reports confirm that the water they purchase meets the stated quality standards. While federal regulations set minimum safety requirements, periodic independent tests help hold manufacturers accountable and provide a clearer picture of the product's quality. This transparency allows consumers to make more informed choices about their hydration habits.
