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Lisa Scholl

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pH value water

The pH value of water can be determined using the following methods: ✅Potenciometry ✅ISFET ✅Indicator

The water that is used is constantly checked for various values. One of them is the pH value. It gives us information about whether a solution – in this case water – has an acidic or basic character. Since we humans need for our health a balanced acid-base balance need, our drinking water must also have a certain pH value. If the acid-base balance is in equilibrium, it is at its optimum.

What is meant by the pH value?

A pH value (measure of hydrogen ion concentration) is expressed as a simple number between 0 and 14. It indicates the hydrogen and hydroxide ion activity in aqueous solution. In pure water, a few water molecules are always split into a hydrogen ion and a hydroxide ion. Different beverages also have different pH values:

  • Coffee: pH 5

  • Wine: pH 4

  • Cola: pH 2-3

  • Beer: pH 4.5

What is the pH value of water?

Anything below the neutral value of 7 on the pH scale is considered acidic. Anything above this is called basic or alkaline. The further the value deviates from 7, the stronger the acid or base.

Different types of water have different pH values:

  • Distilled water: pH value 5

  • Tap water/drinking water: pH value 7 – 8.5

  • Rainwater: pH value 5.6 – 5.8

  • Carbonated mineral water: pH 5.5 – 6.5

  • Heating water: pH value 8.2 – 1o

  • Lime water: pH value 12

The optimum pH value for drinking water

Our drinking water is strictly controlled in terms of pH. The drinking water ordinance stipulates that tap water must have a pH value between 6.5 and 9.5 . Thus, the water is in the neutral to basic range of the pH scale.

The importance of the pH value in drinking water

If the samples do not meet the requirements, the regional water suppliers intervene and regulate the water. Both human health and the material resistance of the pipes depend on an appropriate pH value.

From an economic standpoint, it is critical for utilities and homeowners to maintain a constant pH. This has a significant impact on the choice of material for water pipes. If these specifications are not met, there is a risk of corrosion.

  • Galvanized steel: At a pH value of less than 7.5, corrosion may occur on galvanized steel pipes. This can lead to material deterioration or changes.

  • Copper pipes: Copper pipes release more copper into the water when the pH is below 7.

  • Cementitious materials: Cementitious materials are damaged by acidic water with a pH value between 4 and 6.5.

Drinking water pipes made of corrosion-resistant steel, internally tin-plated copper or plastic are harmless materials. The different pH values of the water affect both the pipes and the human body.

Acidic or alkaline?

The health and well-being of the body are strongly influenced by the food you eat. Alkaline water consumption, in particular, is becoming increasingly popular and water ionizers are being touted for their health benefits.

Alkaline water does not occur in nature and must therefore be produced with expensive treatment plants. There is no clear evidence for the regular and high consumption of alkaline water for its health benefits or its mode of action in the human body. There are even trends that suggest that regular and heavy consumption of alkaline water can lead to excess stomach acid.

Furthermore, an alkaline or acidic food is not determined by the label, but by its effect on the body. This therefore also includes foods that activate the body’s own alkaline formation, but which do not have an alkaline pH value when eaten. The same applies to the acid balance. An organism needs an optimal pH value to maintain the balance between acids and bases and thus health.

How is the pH value in the water measured?

The pH value of drinking water can be measured using various methods. In the so-called potentiometry method, a glass sphere filled with a buffer solution is immersed in the water to be measured. An electromotive force is created between the inside and outside of the sphere by the inclination of the hydrogen ions, which depends on the pH value. This voltage is measured with two reference electrodes.

Using the ion sensitive field effect transistor (ISFET), it is apparent through the gate membrane that a voltage is building up. The pH value of a liquid can be determined from this measurable voltage signal.

An indicator dye is used to determine the pH of the water in a much simpler way. The color changes of indicator substances are measured visually and checked for colorimetric consistency using a color comparison scale. A good example of this is the use of measuring strips with different colored and adjacent fields, which leads to optimally readable results.

How does the pH value influence the human organism?

A wrong and unhealthy diet can disturb the acid-alkaline balance of the body, which has a negative effect on health and well-being.

When the optimal blood plasma pH of 7.41 is either raised or lowered too much, a pathological condition results. These strong deviations from the optimal pH value can no longer be regulated by the body and lead to death.

A diet high in processed foods often leads to mild acidity of the body. However, hyperacidity is not synonymous with temporary heartburn. Rather, the condition results from ingesting foods that stimulate acid production in the body over an extended period of time.

The acid-base balance in the body

The pH value in the body can be strongly influenced by a balanced diet. This is because the selection of foods can itself determine which acidic or alkaline pH values are formed when the nutrients are processed. Eating too many acid-forming foods, such as animal proteins or convenience foods, can over-acidify the body.

Symptoms of hyperacidity include fatigue and exhaustion, poor performance and concentration, muscle and joint pain, nervousness and sensitivity to stress. Diseases such as arthritis or even strokes in advanced age can also be the consequences.

Such severe hyperacidity cannot be neutralized with pH-neutral drinks alone. In particular, sufficient alkaline-forming foods such as fresh vegetables, herbs, fruits, carrots, whole grains, berries and nuts must be consumed to balance out hyperacidity in the body.

Tap water is a good alternative

It is therefore important to also monitor the pH value of the drinking water. Many liquids are detrimental to health and upset the acid balance. Tap water, which is of excellent quality and can be drunk as drinking water, can certainly be an excellent addition to the daily diet. However, this is not true for every place and every water source.

While it cannot always be guaranteed that drinking water will survive transport from the waterworks without contamination, it is nevertheless scrupulously controlled, and the legal framework is stricter than for any other foodstuff. Numerous studies have proven that tap water is just as good as bottled water.

In many places, tap water has the same mineral concentration as the commercially available product. Water contains minerals such as calcium and magnesium, which are important for maintaining healthy bones and muscles as well as nerve function. Sodium, potassium and sulfate in water also play an important role in maintaining health.

The pH value in the water for other areas

For private individuals, it is not necessary to lower or raise the pH of the water for normal consumption – this is done by the regional water suppliers. However, there are some situations where a certain pH is required, for example for an aquarium or swimming pool.

Aquarium pH value

Because fish experience significant problems when the pH in their habitat is not appropriate, maintaining the proper pH in the aquarium is critical. However, it does not always correspond to the value preferred by the fish.

In such cases, pH adjustment is required. An excess of CO2 lowers the pH value. More surface flow (current) expels CO2 and thus increases the pH. If this fails, water conditioners can also be used.

pH value in swimming pool

Ideally, the pH value in the pool is between 7.0 and 7.4. If the pH deviates from this range, it can be corrected with water conditioners such as pH-Plus and pH-Minus.

The pH value in swimming pools can be affected due to other influencing factors such as rainwater or undissolved solids (impurities). They consist of organic and inorganic particles. Organic substances are produced by everything that lives, such as animals and plants. Non-living substances such as sand and stones are inorganic substances. This is where the TDS value can help to find out how clean or dirty the pool water is.

Frequently asked questions about the pH value in water

When it comes to the topic of the pH value of water, questions arise again and again. The most frequently asked questions are answered below.

What pH value of water is good?

The optimum pH range for water is between 7.0 and 8.5. Water supply systems and also people benefit from pH levels within this range.

What pH value of water is dangerous?

The German Drinking Water Ordinance sets the pH value for drinking water at 6.5 to 9.0. If the values deviate from this, this can have a negative impact on people and the environment.

Why is the pH value of water not always neutral?

The pH value of a water is determined by the amount of hydrogen ions present. When there are many hydrogen ions, the pH is low, which means that the water is acidic. If few hydrogen ions are present, the pH is high, which means that the water is basic.

The conclusion – a neutral pH value for drinking water is ideal

Acidic water is not only harmful to the human body, but also damages the plumbing if the pH is below 7 or above 8.5. For drinking water, the pH value should therefore be in this range.

However, pH-neutral beverages cannot balance the acid-base balance. Therefore, attention should be paid to a balanced, healthy and base-forming diet and sufficient pure water should be drunk. It is quite easy to assess the water quality. It varies from region to region, but is in no way inferior to bottled water.


Legionella: How long to run water?

Legionella can be found wherever there is water. These are rod-shaped bacteria that reside in freshwater and multiply intracellularly depending on the water temperatures prevailing there. The ideal conditions for Legionella are at temperatures between 25 and 50 degrees and in surfaces wetted with water, such as water pipes, fittings or even air conditioning systems.

Especially in older, poorly maintained or even little used water pipes there is an increased risk of legionella. However, calcification or materials such as rubber or plastic can also promote legionella proliferation.

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When preparing the morning tea, many users are then annoyed by large, white chunks of lime floating in the water and looking unappetizing. In addition, many are reluctant to consume the hard tap water straight and forego lugging heavy crates of beverages.

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