It decided that adding fluoride to drinking water was technically a kind of medication - which people should be able to choose not to have under the Bill of Rights Act - but that the council's power to add fluoride was a "justified limit" on that right.
Two years earlier, in 2016, legislation that would allow district health boards, rather than councils, to decide whether drinking water was fluoridated began its passage through Parliament.
That Health (Fluoridation of Drinking Water) Amendment Bill is still not law.
The addition of fluoride to Waverley's water might have taken a long time, but it shocked and dismayed Vallely, who read about it in a letterbox drop made on June 8.
He believes fluoride can be toxic and said he was a concerned citizen.
"100 per cent pure New Zealand has just gone out the window," he said.
He's now buying drinking water from alternative sources.
But Jarman congratulated the council on the plant. He said drinking water was something people take for granted, but problems with it can cause a lot of illness very quickly.
South Taranaki mayor Phil Nixon is also pleased to see the plant completed and operational because Waverley had been experiencing some issues with the town water supply.
"The council has been working to address this and has built a new $2.1 million water treatment plant for the town," Nixon said.
"The new Waverley plant will help ensure the town has safe drinking water that fully meets the Drinking Water Standards for New Zealand."
Waverley's water comes from a reservoir and South Taranaki District Council community and infrastructure services manager Fiona Aitken said the new treatment plant uses several processes to remove bacteria, organic matter and inorganic matter, such as iron and manganese compounds, from the water.
The methods include using ultraviolet light to kill protozoa and other bugs. Chlorination and fluoridation are also part of the treatment process.
