This standard describes a method for the determination of chemical oxygen demand, COD, by the dichromate method. The method is applicable to most waters in which the COD is greater than 30 mg/l. The maximum COD value that can be determined in a sample without dissolution is 700 mg/l. The method is not applicable in waters that after dilution contain more than 2 000 mg/l of chloride ions, seawater or brackish waters. Regarding interference, see chapter 9.