Ōtorohanga drinking water comes from the Waipa River and during the summer months as the river level drops and the water temperature increases some people begin to notice a “muddy taste” to the drinking water. Council have carried out testing of the water and those tests have shown minute levels (nanograms) of the organic compounds called Geosmin, and 2-Methylisoborneol, which are associated with the formation and life-cycle of algae and causing the muddy taste and odours. These compounds are not harmful and for instance are responsible for the earthy taste found in beets.
The water is safe to drink and meets all the current New Zealand Drinking Water Standards 2018, but unfortunately humans are very sensitive to Geosmin and can detect it at levels as low as 5 parts per trillion, which means that microscopic amounts can be tasted by people especially sensitive to them.
To help filter the compounds Council are adding activated carbon to the treatment process and will be performing further tests over the next month to check for improvements.