Geosmin increase in Marton water - November 2024
It's that time of year again where people are noticing changes to the water that comes through the taps. It's actually arrived a bit earlier this year, which is due to the unsettled weather we've been having.
November 20, 2024
As most Martonians know, sometimes the water here has a muddy taste and smell, and people often associate that with the water having dirt in it. But, the reason for the taste is actually geosmin.
What is geosmin?
Geosmin is essentially the breakdown of algae, which is more prominent in warmer months. Geosmin is in all surface freshwater sources like rivers, lakes, storage ponds and reservoirs. The smell and taste is more easily detected in warmer water.
Do we treat for geosmin?
Yes, we do impoundment control, which means we identify the best level and area to take water from by testing the PH and dissolved oxygen levels. We also dose the water with activated carbon at the inlet of the water treatment plant, which absorbs the geosmin and we then clarify the activated carbon out of the water. At present, our reticulation team are fine tuning the treatment process, which can take a few weeks for people to notice a difference.
Geosmin can be detected at very low concentrations, and certain people are more sensitive to it than others.
What can you do to help water taste better?
Chilling the water and adding ice cubes has helped some people notice a reduction in the taste and smell of geosmin. Some have also said that lemon slices and/or juice, or a drop of white vinegar can help.
We know that the water at times is not pleasant to drink, but geosmin is not harmful to people or animals, and our water is regularly tested to ensure that it meets Taumata Arowai drinking water standards.
Also, for those that wonder about the filtered water tap at Marton Memorial Hall, the filters are inspected on Monday's and Friday's by our contractors, and they will replace them if needed.
The long-term fix, the Marton Water Strategy, is nearing completion (April 2025) and will see Marton transition from a surface water supply to a groundwater supply, which means no more geosmin in the future.
