Water fluoridation
Chlorine is added at 0.3 ppm and [[Water fluoridation controversy|fluoride]] has been added since 1966, though with a brief withdrawal in 2013/14 and referenda supporting it in 2006 and [[2013 Hamilton local elections and referendums|2013]]. The river water has 0.2 to 0.4 ppm fluoride which is increased to around 0.75ppm through the station. Arsenic [[Waikato River#Environmental issues|in the Waikato River]] is also monitored. It can be about 3 times above the [[WHO]] limit, but treatment effects a 5-fold reduction to a level which meets the standards.