Substances dissolved in water are two groups: organic substances and inorganic substances. Determination of the oxidability of water or determination of total organic matter in water, ie the determination of oxygen in mg / l of water, is considered as an indicator of the level of organic matter present in the water, ie the level of pollution of water.

Organic substances in waters are formed as a result of microbial or environmental pollution. Organic substances are a complex group of substances ranging from very small molecular weight microorganisms to large molecular structures, such as oils, proteins, carboxylic acids, carbohydrates, amino acids, ammonia, nitrate, nitrite, chlorine and hydrocarbons.

The increase in the amount of organic matter in the water tanks is directly related to the physical properties of the pipelines and the water tank. Therefore, the tanks should be cleaned at regular intervals and the system should be improved to prevent organic pollution.

Excess amount of organic matter in water means that there is an environment suitable for microbial growth. However, free chlorine is high in water with a high amount of organic matter, but this is another risk if there is no microbial pollution. Therefore, the amount of organic matter in water (oxidation level) should be closely monitored.

The Regulation on Water for Human Consumption issued by the Ministry of Health regulates the principles for the production, packaging, labeling and inspection of drinking and utility water in compliance with technical and hygienic conditions and quality standards. The annexes to the Regulation include the analyzes to be carried out in the waters and the permissible values ​​of these analyzes. This regulation covers the provisions concerning drinking water and potable water and spring water. According to the regulation, the amount of oxidation of the waters should be maximum 5,0 mg / l oxygen. The more carbon and organic matter in the water, the more oxygen is consumed in the water.

Oxidability determination studies in water are carried out in authorized laboratories within the scope of chemical tests. In these studies, standards and test methods published by national and international organizations are followed.