Urea is an organic contaminant that is mainly introduced into the bath water through human excrements such as urine or sweat. The concentration increases with a high bathing volume or through heat. Urea itself is a crystalline and colourless compound which is completely soluble in water. In water, urea is decomposed by enzymes or bacteria present in the water to CO2 and ammonium. However, the decomposition can also be oxidative. Although urea itself is odourless, so-called chloramines are formed during oxidation with a disinfectant such as chlorine, which are responsible for the characteristic chlorine odour and are also known as bound chlorine. Since active chlorine is consumed in the reaction, a subsequent dosage of the disinfectant may be necessary. Urea is therefore a good indicator of the degree of contamination of bathing water. The detection method is enzymatic, therefore the PL Urea 2 Reagent must be stored at 4°C - 8°C and the sample must be measured at 20°C - 30°C water temperature.