Non-domestic customers can apply for reduction of SC and TES under two situations as depicted below:

Reassessment of discharge factor
A non-domestic consumer can apply for a reassessment of the discharge factor for reduction of SC or TES if the consumer can demonstrate that the volume of sewage discharged into the public sewerage system is not more than 85% of the volume of water on which the SC or TES is based.

Reassessment of COD values and TES rate
A consumer liable to pay TES can apply for a variation of the TES rate if the consumer can demonstrate that the pollution level of his discharge is lower than the prescribed generic COD values of his trade. This can be done by having the pollution level of the trade effluent reassessed at his own expense by an approved laboratory in accordance with the Technical Memorandum issued by the former Secretary for the Environment, Transport and Works. Upon satisfactory completion of the reassessment, a revised TES rate will be determined according to the charging rate matrix shown in Schedule D and will take effect for three years. Detailed application procedures are given in “Guidelines on application for Reassessment of Chemical Oxygen Demand under Sewage Services (Trade Effluent Surcharge) Regulation"