WATER QUALITY Water Quality Annual Report 2017/18 1800 454 500 I [email protected] www.gvwater.vic.gov.au Water Quality Annual Report 2017-18 TABLE OF CONTENTS 1 INTRODUCTION...................................................................................................................6 1.1 water supply systems ............................................................................................................. 9 1.3 Source water protection ...................................................................................................... 12 1.4 Improvements to water supply and treatment .................................................................. 12 1.5 Changes to water sampling localities ................................................................................ 13 2 WATER TREATMENT AND QUALITY MANAGEMENT SYSTEMS ...................................... 14 2.1 Water treatment .................................................................................................................. 14 2.1.1 Raw Water and Pre-Treatment ................................................................................... 14 2.1.2 Chemical addition, coagulation and flocculation ..................................................... 15 2.1.3 Clarification, Sedimentation and Flotation................................................................ 16 2.1.4 Filtration ....................................................................................................................... 16 2.1.5 Disinfection.................................................................................................................. 16 2.1.6 Fluoridation ................................................................................................................. 17 2.1.7 Clear water storage (storage of treated water) ......................................................... 17 2.1.8 Reticulation (supply to the customers tap) ............................................................... 17 2.2 Changes to water treatment processes and chemicals ................................................... 20 3 QUALITY OF DRINKING WATER ...................................................................................... 21 3.1 Escherichia coli .................................................................................................................... 21 3.1.2 Results ......................................................................................................................... 22 3.1.3 Actions in relation to non-compliance ....................................................................... 24 3.2 Chlorine based disinfection by-product chemicals ........................................................... 24 3.2.1 Results ......................................................................................................................... 25 3.2.2 Actions in relation to non-compliance ....................................................................... 26 3.2.3 Actions and preventative measures taken in relation to non-compliance ............. 32 3.3 TURBIDITY ............................................................................................................................ 34 3.3.1 Results ......................................................................................................................... 35 3.3.2 Actions in relation to non-compliance ....................................................................... 36 3.4 Aluminium ............................................................................................................................ 36 Page 2 of 89 Water Quality Annual Report 2017-18 3.4.1 Results ......................................................................................................................... 37 3.4.2 Actions in relation to non-compliance ....................................................................... 39 3.5 Fluoride ................................................................................................................................ 39 3.5.1 Results ......................................................................................................................... 40 3.5.2 Actions in relation to non-compliance ....................................................................... 41 3.6 Other Chemicals That May Pose a Risk To Public Health ................................................. 41 3.6.1 Results ......................................................................................................................... 42 3.6.2 Actions in relation to non-compliance ....................................................................... 63 3.7 Aesthetics............................................................................................................................. 63 3.7.1 Results ......................................................................................................................... 64 3.7.2 Actions in relation to Aesthetic Issues....................................................................... 72 3.8 Analysis of results ................................................................................................................ 73 3.8.1 Water Quality Standards ............................................................................................ 73 4 EMERGENCY AND INCIDENT MANAGEMENT ................................................................ 75 4.1 Known or Suspected Contamination ................................................................................. 76 4.1.1 Section 22s ................................................................................................................. 76 4.1.2 Blue Green Algae Events ............................................................................................ 77 5 COMPLAINTS RELATING TO WATER QUALITY ................................................................ 79 5.1.1 Analysis of water quality complaints ......................................................................... 81 5.1.2 Customer Engagement around Water Quality .......................................................... 82 6 FINDINGS OF THE MOST RECENT RISK MANAGEMENT PLAN AUDIT ........................... 84 7 UNDERTAKINGS AND EXEMPTIONS UNDER SECTION 30 OF SDWA ............................ 85 8 REGULATED WATER ....................................................................................................... 86 9 FURTHER INFORMATION ............................................................................................... 89 List of Tables Table 2.1.1.1: GVW Raw Water Sources and Localities Serviced.................................................... 11 Table 2.1.8.1: GVW Treatment Processes ........................................................................................ 18 Table 2.1.8.2: Water Treatment Chemicals ...................................................................................... 19 Table 3.1.2.1 Escherichia coli (Reticulation) .................................................................................... 22 Table 3.1.2.2: Escherichia coli (Clear Water Storage) ...................................................................... 23 Page 3 of 89 Water Quality Annual Report 2017-18 Table 3.2.1.1: Chlorine based disinfection by-product chemicals – Trihalomethanes .................. 25 Table 3.2.2.1 Chlorine based disinfection by-product chemicals – Chloroacetic Acid .................. 27 Table 3.2.2.2 Chlorine based disinfection by-product chemicals – Dichloroacetic Acid ............... 29 Table 3.2.2.3 - Chlorine based disinfection by-product chemicals – Trichloroacetic Acid ............. 31 Table 3.2.3.1: Health related parameters – Chloral hydrate in Drinking Water ............................. 33 Table 3.3.1.1 Turbidity........................................................................................................................ 35 Table 3.4.1.1: Acid Soluble Aluminium (Reticulation) ...................................................................... 37 Table 2: Acid Soluble Aluminium (Clear Water Storage) .................................................................. 38 Table 3.5.1.1: Fluoride in Drinking Water ......................................................................................... 40 Table 3.6.1.1: Health related parameters – Arsenic in Drinking Water .......................................... 43 Table 3.6.1.2: Health related parameters – Barium in Drinking Water .......................................... 44 Table 3.6.1.3: Health Related Parameters – Cadmium in Drinking Water ..................................... 45 Table 3.6.1.4: Health related parameters – Free Chlorine in Drinking Water (Reticulation) ........ 46 Table 3.6.1.5: Health related parameters – Free Chlorine in Drinking Water (Clear Water Storage) ............................................................................................................................................................. 47 Table 3.6.1.6: Health related parameters – Chromium in Drinking Water ..................................... 48 Table 3.6.1.7: Health related parameters – Copper in Drinking Water .......................................... 49 Table 3.6.1.8: Health related parameters – Lead in Drinking Water .............................................. 50 Table 3.6.1.9: Health Related Parameters – Manganese in Drinking Water ................................. 51 Table 3.6.1.10: Health related