2020/21: Swan Hill (Victoria) – Fluoride 1.4mg/L (max), 0.53mg/L (av.)

2022/23: Swan Hill (Victoria – Fluoride >1.5mg/L

LMW reported one instance of known or suspected contamination as required by Section 22 of the Act. A Section 22 report was submitted to DH on 27 June 2023 under the Code of Practice for Fluoridation of Drinking Water Supplies (Vic) for fluoride concentration in drinking water supplied, or to be supplied, exceeds 1.5 mg/L for the Swan Hill reticulation. The incident happened during a planned shutdown on 5 May 2023 to replace the switchboard. Upon resumption of fluoride dosing, DH was notified on 23 May 2023. The investigation into
the event revealed that fluoride concentration after the treated water storage tank exceeded 1.5 mg/L.
As the treated water fluoride analyser measures the concentration of fluoride in water to be supplied, LMW submitted a s22 report. The root cause for the high fluoride concentration was due to insufficient dilution during flushing of the dosing lines. In response to the incident a procedure was developed for manual startup of the fluoride dosing system. Lesson learned
was shared among the operators in their toolbox meeting. A debrief was held between DH and LMW on 21 July 2023 where four action groups were identified and LMW is working towards implementing them.

Based on health considerations, the concentration of fluoride in drinking water should not exceed 1.5 mg/L.

“Fluoride occurs naturally in seawater (1.4 mg/L), soil (up to 300 parts per million) and air (from volcanic gases and industrial pollution). Naturally occurring fluoride concentrations in drinking water depend on the type of soil and rock through which the water drains. Generally, concentrations in surface water are relatively low (<0.1–0.5 mg/L), while water from deeper wells may have quite high concentrations (1–10 mg/L) if the rock formations are fluoride-rich.” 2011 ADWG.