• Equipment preparation: Cleaning and disinfection of equipment. • Sampling procedure: Collection technique and contamination control. • Sample handling and preservation: Use of sterile containers and appropriate labeling. The attribute assessment will be documented for each organization, ensuring a record of compliance at each stage of the sample collection.A qualified ILT professional, independent of the participating organizations, will be present during the sample collection process. Instruction Manual for the Collection, Preservation, and Transportation of Drinking Water Samples for Laboratory Analysis ISBN: 978-958-13-0147-8 issued by the INS, and any documents that update or modify it. Determination of Dissolved Solids and Total Iron (with on-site conductivity, pH, and residual chlorine measurement report) ISO 11885