Nutrition Diet: What makes water alkaline?

October 15, 2025 •

4 min read

Over 50% of the world's freshwater sources have natural alkaline properties, largely due to their geological environment. This article explores what makes water alkaline, examining both natural and artificial processes, and discusses its place within a balanced nutrition diet.

Quick Summary

Water's alkalinity is determined by its mineral content, primarily dissolved carbonates, bicarbonates, and hydroxides from geological sources like limestone. While some waters are naturally alkaline, others achieve a high pH through artificial methods such as electrolysis or adding minerals. It is important to distinguish pH from alkalinity, or buffering capacity, and understand potential health implications.

Key Points

Mineral Content is Key: Water becomes naturally alkaline when it dissolves minerals like calcium, magnesium, carbonates, and bicarbonates from rock formations, such as limestone.
Alkalinity vs. pH: Alkalinity measures a water's buffering capacity to neutralize acids, while pH is a scale indicating hydrogen ion concentration. Alkaline water has a pH above 7, but its true buffering capacity comes from its mineral content.
Natural vs. Artificial: Natural alkaline water gets its properties from geological processes, while artificial versions use electrolysis (ionizers) or additives like baking soda or pH drops to increase the pH.
Health Claims are Debatable: While some limited studies suggest benefits for conditions like acid reflux or hydration, most broad health claims about alkaline water lack robust scientific evidence.
The Body Regulates its Own pH: The human body has effective systems (lungs and kidneys) to maintain a stable blood pH level, making it unlikely for drinking alkaline water to significantly alter it for extended periods.
Potential Risks Exist: Excessive intake of high-pH alkaline water, particularly artificially processed versions, can potentially disrupt natural stomach acidity, cause mineral imbalances, and, in rare cases, lead to alkalosis.

The Science of Water's pH and Alkalinity

To understand what makes water alkaline, it's crucial to first grasp the difference between pH and alkalinity. The pH scale, ranging from 0 to 14, measures the concentration of hydrogen ions ($H^+$) in a liquid. A pH of 7 is neutral, anything lower is acidic, and anything higher is alkaline or basic. While pH is a measure of current acidity or alkalinity, alkalinity is a measure of the water's buffering capacity—its ability to resist changes in pH when an acid is added. This buffering capacity is a key indicator of water's stability and is directly related to its mineral content.

The ions that contribute to a water body's alkalinity are typically carbonates ($CO_3^{2-}$), bicarbonates ($HCO_3^-$), and hydroxides ($OH^-$), with bicarbonates being the most prevalent in natural settings. These compounds neutralize acids by reacting with excess hydrogen ions, preventing the water's pH from dropping. This process is vital for aquatic ecosystems and can also influence the water's properties when consumed.

Natural Sources of Alkaline Water

Nature plays a significant role in creating alkaline water. The most common natural process involves water passing over mineral-rich rocks and soil. As rain or groundwater flows through the earth, it dissolves minerals, absorbing them into the water.

Geological influences on natural alkalinity:

Limestone and chalk: Areas with large deposits of calcium carbonate, such as limestone and chalk, will produce water with high alkalinity. The water dissolves the rock over time, infusing it with calcium, bicarbonate, and other minerals.
Other rocks and soil: While limestone is a primary source, other mineral deposits can also contribute. Runoff from soils and the decomposition of organic matter can also introduce alkaline substances into water sources.
Springs: Water from natural springs is often naturally alkaline, having traveled through and collected minerals from subterranean rock formations. Many naturally sourced bottled alkaline waters come from these types of springs.

Methods for Artificial Alkalization

Beyond what nature provides, technology and simple kitchen ingredients can be used to produce alkaline water.

Artificial methods include:

Electrolysis (Water Ionizers): This chemical process uses electricity to separate water into acidic and alkaline streams. The resulting alkaline water has a higher pH, often without the same natural mineral content as spring water, unless added separately.
Mineral Drops: Concentrated mineral drops containing alkaline substances, such as potassium and magnesium, can be added to regular water to increase its pH. This is a simple, portable method for on-the-go alkalization.
Baking Soda: Adding a small amount of baking soda (sodium bicarbonate) to water is an easy at-home method to increase its pH. A common recommendation is to mix about 1/8 teaspoon into 8 ounces of water.
Alkalizing Fruits and Vegetables: Adding lemon or cucumber slices can have an alkalizing effect on the body after metabolism, though the water itself remains acidic until consumed.

Comparing Alkaline and Regular Water


Feature	Alkaline Water (Typically pH 8-9.5)	Regular Drinking Water (Typically pH around 7)
pH Level	Higher than 7 (alkaline)	Around 7 (neutral)
Mineral Content	Naturally alkaline water has high mineral content (calcium, magnesium). Artificially made water can have added minerals.	Can vary significantly depending on the source.
Taste	Some describe it as smoother or sweeter.	Can range from neutral to slightly metallic based on mineral composition.
Production	Occurs naturally by dissolving minerals or produced artificially by electrolysis or additives.	Sourced from taps or bottles without pH adjustment.
Health Claims	Supporters suggest benefits for hydration, acid reflux, etc., but evidence is often inconclusive or requires more research.	Provides standard hydration, widely considered safe and sufficient for most people.

The Nutrition Diet Debate: Potential Benefits and Risks

While some potential health benefits of alkaline water have been suggested, the scientific community holds mixed views. Some studies point to specific benefits, while many health professionals caution that robust, long-term research is still lacking.

Potential benefits noted in some studies:

Improved Hydration: Some studies suggest alkaline water may offer superior hydration, especially after exercise.
Acid Reflux Relief: A 2012 study suggested that alkaline water with a pH of 8.8 may help deactivate pepsin, an enzyme linked to acid reflux.
Bone Health: Research has suggested that alkaline mineral water might have a positive impact on bone density.
Cardiovascular Health: A 2016 study found that people with high blood pressure, blood sugar, and cholesterol who drank alkaline water for several months showed some improvements.

Despite these findings, it is crucial to remember that the human body is designed to regulate its own pH levels naturally, primarily through the kidneys and lungs. Drinking alkaline water has a minimal and temporary effect on overall blood pH.

Potential risks and considerations:

Disrupting Stomach Acid: Consuming excessive alkaline water might temporarily alter the acidic environment needed for proper digestion and to kill harmful bacteria.
Mineral Imbalance: Overconsumption can cause a mineral imbalance, potentially interfering with the absorption of other vital nutrients like iron and zinc.
Alkalosis: In rare cases, especially with very high pH water, excessive intake could lead to metabolic alkalosis, causing symptoms like nausea and hand tremors.
Purity Concerns with Ionizers: The quality of artificially ionized water depends on the source water. If the source is not properly filtered beforehand, an ionizer could concentrate contaminants.

Conclusion

Understanding what makes water alkaline involves appreciating the role of dissolved minerals, whether sourced naturally from geological formations or added through artificial processes. For most people, regular, clean tap water or bottled water is sufficient for hydration and offers no disadvantages compared to alkaline water. While some studies suggest limited benefits for specific conditions like acid reflux or hydration, the broad health claims often lack definitive scientific support. For those considering a dietary change like regularly consuming alkaline water, especially those with pre-existing health conditions, consulting a healthcare professional is always advisable. The most important aspect of any nutrition diet is consistent, healthy hydration, regardless of the water's pH level.

For additional information on hydration and diet, consult reliable sources such as the Mayo Clinic.

Frequently Asked Questions

Alkaline water typically has a pH level between 8 and 9.5, which is higher than the neutral pH of 7 found in regular drinking water.

You can make alkaline water at home by adding a small amount of baking soda (sodium bicarbonate) or pH drops to regular water. Using a water ionizer is another method, but it is more costly.

Yes, natural alkaline water gains its alkalinity and mineral content from passing over mineral-rich rocks. Artificial alkaline water is often produced via electrolysis, which can separate ions but may not contain the same beneficial natural minerals.

While alkaline water has a higher pH, the human body has its own robust mechanisms to maintain a stable blood pH. Any effect from drinking alkaline water is minimal and temporary.

Excessive consumption can disrupt natural stomach acidity, potentially leading to issues with digestion and nutrient absorption. In rare cases, it can cause metabolic alkalosis or mineral imbalances.

There is no conclusive evidence that alkaline water is significantly better than regular water for hydration for most people. While some studies suggest potential benefits, more research is needed.

Individuals with kidney disease or impaired kidney function should avoid drinking alkaline water, especially ionized versions, without consulting a doctor, as it can be risky.

Bicarbonate ($HCO_3^-$) is the primary mineral contributor to alkalinity in most natural waters, originating from dissolved atmospheric carbon dioxide and mineral weathering.