We have received confirmation that Geosmin is the cause of the recent unpleasant odors in our tap water. Lab results from Monday afternoon revealed Geosmin levels of up to 60 parts per trillion in the distribution system and over 70 parts per trillion in the raw water. For context, humans can detect Geosmin at concentrations as low as 4-5 parts per trillion.
This week, we will be conducting additional sampling to determine if the bloom has subsided. Once Geosmin levels decrease, we plan to deep cycle the reservoirs and perform selective flushing. These actions should improve water quality faster than waiting for Geosmin to naturally dissipate in the distribution system.
In case you missed our previous update from Friday, here’s a summary:
You may have noticed some unpleasant odors in your tap water recently, and we want to assure you that the water is safe to drink. Tests have ruled out harmful toxins related to algae and cyanobacteria. While the water may not smell as fresh as usual, it remains safe for consumption.
We are actively working to address this issue and initially suspected Geosmin or Methyl-Isoborneol (MIB) as the culprits. These compounds naturally occur in rivers and lakes, including the Rogue, our water source. The latest test results have now confirmed Geosmin as the source of the odor.
We expect the odors to dissipate within a few days. In the meantime, using activated carbon filters found in household water filtering pitchers can help mitigate the odor.
For more information about MIB and Geosmin, you can follow this link to an article from the EPA.
