According to Hanna Instruments , chloride is one of the most common ions present in water. In drinking water, its level must be kept low because it can badly alter the taste. In other applications, the chloride level must be monitored to prevent scaling and corrosion. In high concentrations, chloride can corrode even stainless steel and it is very dangerous for vegetation. HANNA instruments® presents a new test kit for chloride analysis. HI 3898 allows the user to determine high concentration of chloride in wastewater, which can interfere with official COD analysis methods. This test, according to the ISO 15705:2002 method indicates chloride interference in seconds. The concentration is considered too high if the chloride concentration is higher than 1000 ppm (for COD test according to the ISO directives) or higher than 2000 ppm (for COD test according to the USEPA, APHA, AWWA and WEF methods). If a high concentration of chloride is found, the sample must be diluted.