Water Education - Water and Health

pH of Water, What It Is and Why It Matters


Remember the time in 4th grade science class when you did that experiment with litmus paper and it turned red when you put it on a lemon and blue in soapy water? That was probably your first experiment into the wondrous science of pH.

Water is an essential element for all life forms, and its quality is of utmost importance. One factor that affects water quality is its pH. pH is a measure of the acidity or alkalinity of a solution. In this article, we will explore the pH of water, its importance, and how it affects water quality.

What is the pH of water?

So, what does pH mean for water? Basically, the pH value is a good indicator of whether water is hard or soft. The pH of water can vary depending on the source and the surrounding environment. The natural pH of pure water is 7, which is considered neutral. However, when water comes into contact with other substances, such as minerals or pollutants, its pH can change.

What is the safe range for drinking water pH levels?

pH is measured on a logarithmic scale from 0 to 14, with each unit representing a tenfold difference in acidity or alkalinity. Alkalinity is measured in parts per million (ppm). The safe range for drinking water pH levels is between 6.5 and 8.5. This range is considered optimal for human consumption and ensures that the water is free from harmful contaminants. Drinking water with a pH outside this range may affect its taste, quality, and safety.

Let’s take a look at how the pH of water compares to other common liquids.

Battery Acid0
Stomach Acid1.5-3.5
Lemon Juice2-3
Orange Juice3-4
Tomato Juice4-4.5
Pure Water7

In addition, many of the foods we eat contain an acidic pH because of their bacteria fighting functions.

Why is pH important?

pH is important because it affects the chemical properties of water and how it interacts with other substances. For example, water with a high pH can cause mineral deposits to form, while water with a low pH can dissolve metals and other materials. pH also plays a crucial role in biological processes, and even small changes in pH can impact the health of both aquatic life and human life.

How does pH affect water quality?

The pH of water can affect its taste, odor, and color, making it less appealing for human consumption. Water with a high pH may also be corrosive and cause damage to pipes and plumbing systems. Additionally, pH can affect the solubility of contaminants in water, making some chemicals more harmful at certain pH levels.

According to a Wilkes University study, the association of pH with atmospheric gasses and temperature is the primary reason why water samples should be tested on a regular basis. The study says that the pH value of the water is not a measure of the strength of the acidic or basic solution, and alone cannot provide a full picture of the characteristics or limitations with the water supply.

Acidic vs. Alkaline Water

The pH of pure water is 7. Acidic and alkaline are terms used to describe the pH of a substance. Acidic substances have a pH below 7, while alkaline substances have a pH above 7. Acids have a higher concentration of hydrogen ions, while alkaline substances have a lower concentration.

Alkaline Water

Alkalinity refers to the ability of water to neutralize acids. It is a measure of the concentration of bicarbonate, carbonate, and hydroxide ions in the water. The alkalinity of water can affect its pH and buffering capacity, which is its ability to resist changes in pH. Alkaline water has a pH above 7 and is often associated with health benefits, but excessive alkalinity can also have negative effects on human health and the environment.

Acidic Water

In general, water with a pH < 6.5 could be acidic, soft, and corrosive. Acidic water could contain metal ions such as iron, manganese, copper, lead, and zinc. In other words, acidic water contains elevated levels of toxic metals. Acidic water can cause premature damage to metal piping, and have associated aesthetic problems such as a metallic or sour taste. It can also stain laundry and cause "blue-green" color staining on sinks and drains. More importantly, there are a number of health risks associated with these toxins.

Risks and consequences of unusual pH levels in water

Marine Life: One of the most significant consequences of unusual pH levels in water is the acidification of oceans and lakes. When the pH of water drops below 7, it becomes more acidic, which can have devastating effects on marine life. Many aquatic species have specific pH requirements for survival and reproduction.

Changes in pH can disrupt the chemical balance of the water and make it difficult for these species to thrive. For example, low pH levels can cause fish to become disoriented and affect their growth and reproductive abilities. Acidification can cause shellfish and coral to dissolve, disrupt the food chain, and ultimately harm commercial fishing and tourism industries.

Human Life: Water with a low pH can be corrosive and cause lead and other metals to leach into the water, which can be harmful to human health. Water with a high pH can have a bitter taste and make it difficult for the body to absorb essential minerals. Additionally, changes in pH can affect the effectiveness of water treatment methods, leading to potential health risks.

While the ideal pH level of drinking water should be 6 to 8.5, the human body maintains pH equilibrium on a constant basis and will not be affected by water consumption. For example, our stomachs have a naturally low pH level of 2 which is a beneficial acidity that helps us with food digestion.

Natural factors that influence the pH of water

There are several natural factors that can influence the pH of water, including:

Geology: The type of rocks and minerals in the surrounding soil can affect the pH of water. For example, limestone can increase the pH of water due to its high alkalinity.

Photosynthesis: Plants can absorb carbon dioxide from the water during photosynthesis, which can increase the pH of the water.

Rain: Rainwater is naturally acidic due to the presence of carbon dioxide, which can lower the pH of water.

Man-made factors that influence the pH of water

Human activities can also influence the pH of water, including:

Industrial discharges: Many industrial processes can release acidic or alkaline chemicals into the water.

Agricultural runoff: Fertilizers and other chemicals used in agriculture can leach into the water.

Mining: Mining activities can release heavy metals and other chemicals into the water.

How to conduct a pH test

pH tests are simple and can be done using pH test strips or a pH meter. To test the pH of water, simply dip the test strip into the water or insert the pH meter into the water and wait for the reading. The results can be used to determine if the water is safe for human consumption and to identify any potential issues with water quality.

In conclusion, pH is an important factor to consider when assessing the quality of water. Changes in pH can have significant impacts on aquatic life, human health, and the environment. By understanding the factors that influence pH and conducting regular pH tests, we can help ensure that our water is safe and healthy for all.

What to do if your pH levels are off

The primary way to treat the problem of low water pH levels is with the use of a neutralizer. The neutralizer feeds a solution into the water to prevent the water from reacting with the household plumbing or from contributing to electrolytic corrosion. A typical neutralizing chemical is soda ash, also known as sodium carbonate. Sodium carbonate works to increase the sodium content which increases pH. Water with a pH > 8.5 could indicate that the water is hard. Hard water does not only pose a health risk, but can also cause aesthetic problems.

These problems include an alkali taste to the water (making that morning coffee taste bitter!), formation of scale deposits on dishes, utensils, and laundry basins, difficulty in getting soaps and detergents to lather, and the formation of insoluble precipitates on clothing. Scale deposits also contribute to pipe clogging and damages in household appliances.

APEC offers expert level pH neutralizer filters. Get your pH levels where they need to be, for optimal function of your home and health.

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