ANNUAL DRINKING WATER QUALITY REPORT 2018-19 South Gippsland Region Water Corporation Front page image of Korumburra’s Coalition Creek Reservoir courtesy of David Barton. [email protected] 1 Contents 1. Introduction .................................................................................................................................................................................4 Characterisation of the System ..................................................................................................................................................6 Source water system .............................................................................................................................................................6 South Gippsland Water system and major changes for 2018­19 ....................................................................................6 2. Water Treatment and Quality Management Systems ............................................................................................................ 10 Water treatment overview ....................................................................................................................................................... 10 Lance Creek Water Connection and cessation of Korumburra and Poowong WTPs ................................................. 10 Supplementary supply to Lance Creek clear water storage from Melbourne Water ................................................. 10 Water Treatment Issues ............................................................................................................................................................ 15 Quality Management Systems and Continual Improvement ............................................................................................... 15 3. Emergency, Incident and Event Management ........................................................................................................................ 17 Incidents reported under the Safe Drinking Water Act........................................................................................................ 17 Escherichia coli detection – Poowong .............................................................................................................................. 18 Widespread customer complaint due to taste and odour – Leongatha....................................................................... 18 4. Drinking Water Quality Standards .......................................................................................................................................... 19 Analysis Results – Schedule 2 parameters .............................................................................................................................. 20 Escherichia coli .................................................................................................................................................................... 20 Trihalomethanes ................................................................................................................................................................. 22 Turbidity .............................................................................................................................................................................. 23 Analysis Results ­ Other water quality standards (algal toxin, pathogen, chemical or substance that may pose a risk to human health) ....................................................................................................................................................................... 24 Aluminium (acid­soluble and total) ................................................................................................................................. 24 Arsenic ................................................................................................................................................................................. 27 Copper.................................................................................................................................................................................. 28 Cyanogen chloride .............................................................................................................................................................. 29 Chlorine disinfection residual (Free or Total Chlorine) .................................................................................................. 30 Fluoride ................................................................................................................................................................................ 32 Lead ...................................................................................................................................................................................... 34 Manganese .......................................................................................................................................................................... 35 Nitrate and Nitrite .............................................................................................................................................................. 36 Nitrosodimethylamine (NDMA) ....................................................................................................................................... 38 Other inorganic chemicals ................................................................................................................................................. 39 Other organic chemicals .................................................................................................................................................... 40 Raw water monitoring ....................................................................................................................................................... 41 Aesthetics ................................................................................................................................................................................... 42 Colour ................................................................................................................................................................................... 43 Iron ....................................................................................................................................................................................... 44 Alkalinity .............................................................................................................................................................................. 45 Hardness .............................................................................................................................................................................. 47 pH ......................................................................................................................................................................................... 48 Analysis of results ..................................................................................................................................................................... 50 2 Comparison of results for Schedule 2 parameters over three years ............................................................................ 50 Comparison of results of other water quality parameters over three years ............................................................... 50 5. Complaints relating to water quality for 2018­19 ................................................................................................................. 52 Management of complaints ..................................................................................................................................................... 54 Dirty/discoloured water ..................................................................................................................................................... 54 Taste and odour .................................................................................................................................................................. 54 Air in water .......................................................................................................................................................................... 55 Alleged illness ..................................................................................................................................................................... 55 Other complaints ................................................................................................................................................................ 56 6. Findings of the most recent risk management plan audit ................................................................................................... 57 7. Regulated water ........................................................................................................................................................................ 58 Appendices ....................................................................................................................................................................................... 59 Appendix 1: South Gippsland Water’s Drinking Water Quality Policy ............................................................................. 59 Appendix 2: