The legal basis for the charging and collection of SC and TES and other related matters are stated in the Sewage Services Ordinance and the two subsidiary regulations, viz., the Sewage Services (Sewage Charge) Regulation and the Sewage Services (Trade Effluent Surcharge) Regulation. A Technical Memoradum on Procedures and Methods for Sampling and Analysis of Trade Effluents for the Trade Effluent Surcharge Scheme was issued by the former Secretary for the Environment, Transport and Works.