Alkalinity Of Water Definition: What Is The Alkalinity In Drinking Water?

Alkalinity Of Water Definition What Is The Alkalinity In Drinking Water

The alkalinity refers to the measure of the capacity of the water to neutralize the acids. It can measure the bicarbonate, carbon dioxide, hydroxide ions, and carbonate naturally present in the water. 

The pH level of drinking water refers to how basic or acidic it is. The pH level refers to the hydrogen ions found in the water. It stands for ’potential of hydrogen.’ The pH level of the water at normal drinking level, carbonate, and bicarbonate are the main contributors to its alkalinity.

What is Alkalinity in Drinking Water?

Alkalinity is the water’s capacity to resist changes in pH that would make the water more acidic. It also helps protect your health and piping when it comes to drinking water.

The term “buffering capacity” usually denotes this capacity. Alkalinity also refers to the capability of the water to neutralize the acid. This is true that it has a buffering capacity. A buffer is a solution in which acid can be added without changing the concentration of available H+ ions (as in changes in pH). It absorbs the excessive H+ ions and protects the water from fluctuations in pH. 

For example, if you add the same weak acid solution to two vials of water - both with a pH of 7. One is with zero alkalinity or buffering power. The other has a buffering power (e.g., alkalinity of 50 mg/l)- the pH of the zero alkalinity water will immediately drop. In contrast, the pH of the buffered water will change from very little to not at all. The pH of the buffered solution would change when the buffering capacity of the solution is overloaded.

What Changes the Alkalinity?

The pH and the alkalinity level of the well water can be affected by various factors such as acidic sanitizers, rain, fill water, and other product applications that can change the alkalinity level over time. The majority of alkalinity in the surface water is from calcium carbonate, CaCo3, leached from soil and rocks. 

This process is enhanced if the soil and rocks have been broken up for various reasons like urban development and mining. Limestone contains high levels of calcium carbonate. When used to decrease the acidity at homes, it can runoff into surface waters and raise the alkalinity level. 

Alkalinity is important in the treatment of wastewater and drinking water. It can influence the treatment processes such as anaerobic digestion. Water can also become unsuitable for irrigation if it is higher than the natural level of alkalinity in the soil. 

US EPA Category  The concentration of Calcium Carbonate (mg/L) 
Acidified  <1
Critical  <2
Endangered  2-5
Highly Sensitive  10-20
Not Sensitive  >20 

Alkalinity is closely related to the acid-neutralizing capacity (ANC) of a solution. Often, ANC is incorrectly used to refer to alkalinity. But the acid-neutralizing capacity can refer to the combination of the solution and solids available. Examples are aquifer solids and suspended matter. 

How to Measure Alkalinity

Measurement of Alkalinity

Titration is the process that measures alkalinity. The ‘titrant’ is an acid of known strength added to a volume of a treated sample of water. The volume of acid needed to bring the samples to a specific pH level reflects the alkalinity of the sample. A color change indicates the pH endpoint. The unit that expresses the alkalinity is milligrams per liter (mg/l) of CaCO(calcium carbonate).

Alkalinity Of Water Definition What Is The Alkalinity In Drinking Water

Measuring Alkalinity

The U.S. Geological Survey (USGS) uses one common method for measuring alkalinity. It is to take a water sample and add acid to it, then check the pH of the water as acid is added. It takes an initial reading of the water, adds small amounts of acid, stirs it, and then takes its pH. The same steps are repeated many times.

First, the compounds in the water, such as bicarbonates, neutralizes the acids being added. The more acid is added, the more bicarbonates get “used up” as they are neutralized by the acid. Until eventually, all the acid-neutralizing compounds are used up. After this, the acid in the water will linearly lower the pH. The scientist will see this reflection point by viewing a line chart of the amount of acid added to the water and the resulting pH. The point where the change in pH line becomes linear determines the water’s alkalinity.

Here in this picture, a USGS scientist performs an alkalinity titration to determine the alkalinity of a water sample. Note the pH meter in the background, reading 5.477 at the moment. The pH probe is the larger grey tube going into the beaker. The black device on the right side pushes a fixed amount of acid through the white tube that goes into the right side of the beaker of water. The black box on the bottom has a magnet that twirls, which then twirls a small magnet placed in the bottom of the beaker, which keeps the water sample stirred.

Factors Affecting Alkalinity

Geology and Soils

The water system accumulates carbonates if the water passes through soil and rock containing carbonate minerals, such as calcite (CaCO3). Waters with limestone and sedimentary rocks and carbonate-rich soils are high in alkalinity. The Eastern part of the Boulder Creek watershed is one example. Waters with igneous rocks (such as granite) and carbonate-poor solids are low in alkalinity. One example is the western part of the Boulder Creek watershed.

Changes in pH

Since pH and alkalinity are closely related, changes in pH can also affect alkalinity. This is true, especially in a poorly buffered stream.

Sewage Outflow

The effluent from Wastewater Treatment Plants (WWTPs) can increase alkalinity to a stream. The wastewater from our houses also contains bicarbonate and carbonate from the cleaning agents and food residue that we put down our drains.

Alkalinity Degree and Levels

Alkalinity with a pH of higher than 8.3 is mostly carbonate (CO32-). On the other hand, alkalinity with a pH lower than 8.3 is mostly bicarbonate (HCO3-).

Since alkalinity varies due to differences in geology, there are no set standards for alkalinity. Freshwater usually has 20-200 mg/L levels of alkalinity. A total alkalinity level of 100-200 mg/L can stabilize the pH level in a stream. Levels below ten mg/L show that the water is poorly buffered and susceptible to pH changes from natural and human-caused sources.

Why Alkalinity Is Important

To A Body of Water

The alkalinity of your nearby body of water is important to the health and welfare of, for example, a lake. The ecosystem and organisms living in the lake adapted to the water bodies that did not change quickly. Before the arrival of humans, these bodies of water were not subjected to acid rain or chemical spills. The fish in the lake were just fine until the pH and aquatic characteristics of a lake changed much over a short period.

To this day, water bodies are vulnerable to sudden inputs of chemicals, such as those found in acid rain and wastewater. This can cause quick changes in the acid/base balance of a lake - for instance, lowering the pH of the lake water.

To Aquatic Organisms

Fish and other aquatic life need a pH range of 6.0 to 9.0. Since alkalinity buffers against rapid pH changes, the alkalinity helps protect the living organisms who need a specific pH range. Higher alkalinity levels in surface water can buffer acid rain and other acid wastes. This can prevent pH changes that are hazardous to aquatic life. 

To Drinking Water Source

Alkalinity is also important in considering drinking water and wastewater treatment because it influences cleaning processes like anaerobic digestion. When the alkalinity level in water is higher than the natural level of alkalinity in the soil, water may be unsuitable for irrigation.

The pH Level in Drinking Water

Alkalinity Of Water Definition What Is The Alkalinity In Drinking Water

The pH level of the water is measured on a scale of 0 to 14. If the measurement is below 7, it means that the water is acidic. If it is above 7, then the water is alkaline or basic. If it is 7, then the water is neutral.

If the pH level of the water is less than 6.5, then it can contribute to the corrosion of the fixtures and the pipes. Also, how corrosive the water depends upon other factors. Examples of these are the total dissolved solids, water temperature, alkalinity, and hardness.

Furthermore, water with a pH balance of 6.5 is not a health risk. But the corrosive water can dissolve metals like zinc, cadmium, lead, and copper, which are found in the pipes. As such, it can cause increased concentrations of metals in the drinking water. It can lead to health issues in the long run.

Meanwhile, if the pH level is above 8.5, it can contribute to the scale build-up, especially in plumbing.

The Level of Alkalinity in the Water

Alkalinity comprises hydroxides, bicarbonates, and carbonates, which join magnesium, calcium, and lye. You can find such components in antacids like Rolaids or Tums, lye, baking soda, and limestone. If the alkalinity level is high, it will take more acid to lower the water's pH level. One way to think of alkalinity is the ability of the water to neutralize the acid. 

Alkalinity is expressed as ppm calcium carbonate equivalent. The higher the number, meaning the more of these components are found in the water. 

High alkalinity water may lead to a gradual increase in the growing media pH. Whenever the pH level climbs, the availability of various plant nutrients, especially micronutrients like manganese and iron, are negatively affected. This can now result in deficiencies. 

It may now be necessary to introduce mineral acids like phosphoric or sulfuric minerals into the water. Or use acidic media amendments like acid-forming or sulfur minerals. 

On the other hand, low alkalinity water lacks the components that will neutralize the acid. The continued use of acidic formulas may lead to an undesirable decrease in the pH level of the growing medium. 

The water is often deficient in magnesium, calcium, sulfate, or other supplements that may be needed.

Alkalinity Water Testing for Well Water 

The regular testing of the well water for the standard measures of chemical parameters, including the alkalinity and pH level, is a must. Choose an accredited water testing laboratory for this. You can get the special sampling bottles plus the instructions from the laboratory of your choice. The cost of analyzing water samples can range differently. The price can vary depending on the parameters tested plus the lab.

In testing for alkalinity, you have to fill the filtration tube first up to the 5mL line in the water. Then put a red tablet in the water. Seal it and shake it until the tablet disappears. Then the water might turn blue-green. If the water turns pink, then it does not contain alkalinity.

After that, fill the direct-reading titration with the Alkalinity Titration Reagent B. Next, you have to fill the titration whenever the plunger is up to the zero graduation mark. When the plunger is up to the zero graduation mark, put the titration found in the center hole of the titration tube cap.

Slowly depress the plunger until the titrate sample, which is blue-green, changes to pink. Reagent B, which is depressed into the titration as it turns pink, is the available alkaline level of the water. You can measure it by parts per million (ppm) out of 200 ppm.

Other Term for Alkalinity

Another terminology for alkalinity is water hardness. So it is fair to say that alkalinity and water hardness are similar. Both come from sources in nature. As water moves through rocks, it picks up minerals on its way to rivers and lakes. When limestone and dolomite dissolve in water, one half of the molecule is calcium or magnesium (the “hardness”), and the other half is the carbonate (the “alkalinity). This means the level of water hardness and alkalinity in a place will be very similar. But, their measurements are very separate and have very different importance.

Does Alkaline Water Work?

The use of alkaline drinking water is controversial. Some health experts claim that there is not enough research to back up the health claims provided by the sellers and users. Meanwhile, there are differences in research findings related to the type of alkaline water studies.

According to experts, regular water is still the best for people. There are no studies to verify the claims made by alkaline water supporters fully.

But some studies show that alkaline water can be helpful for certain medical conditions. For example, a study done in 2012 found out that drinking naturally carbonated artesian-well alkaline water with a pH level of 8.8 may help deactivate pepsin. This is the main enzyme that causes acid reflux.

Moreover, drinking alkaline ionized water can positively benefit the body, especially for those who have high blood pressure, high cholesterol levels, and diabetes.

A few years ago, on around 100 people, it was found out that there is a significant difference in the viscosity of the blood after taking high pH water. This is in comparison to those who take regular water after a heavy workout. Viscosity refers to the direct measurement of the blood flow via the vessels.

Those who drink water with a high pH level can have a reduced viscosity of 6.3% versus those who drink standard water with 3.36% of viscosity. As such, you can have the blood flowing efficiently with the use of alkaline water. With this, the delivery of oxygen in the body can be increased.

But more research is needed to support these studies. The field needs more research to provide answers to other claims made by those who support alkaline drinking.

Though there is a lack of scientific research, alkaline water supporters believe that it brings various health benefits. It includes:

  • Anti-aging benefits (this is via the liquid antioxidants which absorb faster in the human body)
  • Cleanses the colon
  • Supports the immune system
  • Lose weight
  • Hydrates the skin and detoxifies it
  • Provides resistance against cancer

The proponents also argue that acidic sodas have positive ORPs, which causes multiple health issues. Meanwhile, the alkalinized and properly ionized water have negative ORPs. Green tea has antioxidant properties, and it has a slight negative ORP.

Alkaline Water and its Possible Treatment of Cancer

The use of alkaline water can help counteract the acid found in the bloodstream of the body. It is believed that drinking water with a high pH level can boost metabolism and improve the ability of the body to absorb essential nutrients.

Other theories explain that alkaline water will starve the cancer cells in the body. This is because the cancer cells strive in an acidic environment. More alkaline in the body can potentially stop or slow down the growth of the cancer cells by balancing the pH level of the body.

In sum, alkaline water can have a hydrating effect on the body. For others, it can even improve the symptoms of some diseases such as acid reflux.

But in a body with a regular function, the alkaline water available in retail stores does not cause significant change. This will not cause that much change in the overall acid-base balance in the bloodstream.

How to Use the Alkaline Water

In 2011, the World Health Organization (WHO) issued updated guidelines on drinking water quality. In general, the organization does not make any health-based recommendations or guidelines for the specific pH level of the drinking water.

The guidelines state that the drinking water's pH level does not directly impact the consumers. This is true as water that has been disinfected with chlorine has a pH level of less than 8.0.

If you wish to use alkaline water, you must drink it as you do with tap water. But be aware that drinking too much alkaline water can lead to possible side effects, like having indigestion or an upset stomach.

Risks and Possible Side Effects of Drinking Alkaline Water

In general, drinking alkaline water is safe. However, it can still cause side effects on the human body. Some of the side effects can include lowering the acidity level of the stomach. With this, it can help kill the bacteria in the body. It can expel unwanted pathogens in the bloodstream.

In addition, excessive alkalinity in the human body can cause skin irritations. It can also lead to gastrointestinal issues. Furthermore, it can agitate the normal pH level of the body. This can lead to metabolic alkalosis, a health condition that can cause symptoms like vomiting, nausea, muscle twitching, hand tremors, confusion, and tingling in the face.

Metabolic alkalosis can lead to a decrease in calcium levels in the body. As such, it can damage bone health. But the most common cause of hypocalcemia is not because of drinking alkaline water. It has an under-active parathyroid gland.

Natural or Artificial?

The natural alkaline occurs when the water passes on the rocks, just like in the springs. Then, it picks up the minerals along the way, which causes the increase of the alkaline level.

But modern homes that consume alkaline water buy a product that has been chemically processed via electrolysis.

With this technique, it uses a product which is called the ionizer. It can raise the pH level of regular water. Those who make the ionizers state that the electricity can separate the molecules in the water, which is more acidic and alkaline. After that, the acidic water is removed.

However, experts state that these claims are not supported by worthy research. Before the ionization begins, the source’s water quality is important in ensuring that the contaminants are not available in the drinking water.

On the other hand, other scientists suggest the use of reverse osmosis. With this, it can adequately purify the water before it connects to an alkaline ionizer. As such, it can add minerals and raise the pH level of the water.

The study done by the World Health Organization (WHO) restricts the use of drinking water with low mineral content. This can be created with distillation, reverse osmosis, and other techniques.

Where to get the Alkaline Water?

One can get alkaline water from health food stores or grocery stores. You can also buy it online. You can also have sparkling water, which is high in pH level and is naturally mineralized.

Meanwhile, water ionizers are sold in various large chain stores around the world.

On the other hand, you can also make alkaline water inside your home. Lime and lemon juices are naturally acidic. However, they have minerals that can modify the composition of the water. Just add a squeeze of lime or lemon in the water, and you can now make it more alkaline. Also, you can add drops of baking soda to the water to change its pH level.

Suppose you filter the water to remove its contaminants, re-mineralize, or ionize it. In that case, there is no evidence of the limitation of how much alkaline water you can consume daily.

Safety of the Alkaline Water

Alkalinity Of Water Definition What Is The Alkalinity In Drinking Water

Many health experts are not concerned with the safety of alkaline water. But it is more about the health claims that they made about it.

There is not enough scientific evidence to support the use of alkaline water to treat various health conditions. Several medical experts pose warning on the use of it because of the claims of several marketers.

Drinking alkaline water is indeed generally safe since it contains various natural minerals. However, you must be cautious about the use of artificial alkaline water. This is because it contains fewer minerals than what is necessary for the body. This can contain more contaminants than you have believed. Overall, its overuse can make you deficient in the consumption of the minerals for the body.


In sum, drinking alkaline water is generally safe for the body. It brings benefits for its consumers. However, the claims have not been backed up by quality research. More things are needed to be proven with its use, and it will take more years to learn its health potentials for the human being.

But if you wish to drink alkaline water, you can produce your own using several filters available in the market. You can also avail yourself of the trusted water stores in your locality.

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