Have you noticed changes in the taste and smell of your drinking water? We understand you may have questions regarding the recent increased levels of the naturally occurring taste and odour compounds – Methylisoborneol (MIB) and Geosmin – in our water supply. Below are some answers to your most frequently asked questions.
Note: Some residents are experiencing dirty or discoloured water. This issue is separate from the MIB and Geosmin event. Common causes of dirty or discoloured water include routine maintenance, mains break, internal plumbing and new service works. All instances require further investigation by PMHC before further water use. Learn more about the steps to take if you encounter dirty or discoloured water.
We are currently experiencing an increase in the naturally occurring compounds Methylisoborneol (MIB) and Geosmin in our water supply, with MIB being the dominant compound at present.
These compounds produce a musty, earthy taste and smell, but are safe to drink at the levels present in our drinking water.
It can take less than 10 nanograms per litre of MIB and Geosmin to affect the aesthetics of the water quality. This is the equivalent of just one drop in a household swimming pool.
The taste and odour compounds MIB and Geosmin are produced by certain types of micro-organisms.
These micro-organisms are often present, however warmer water temperatures during our summer season can contribute to increased levels of these organisms in our waterways. This can then lead to a potential increase in MIB and Geosmin.
Yes. Although the taste and odour caused by MIB and Geosmin may be unpleasant, it’s purely an aesthetic issue and not considered a health hazard for humans.
However, if you are experiencing dirty or discoloured water, this is a separate issue, please visit our Dirty or Discoloured Water page and contact Council via our Report an Issue Form.
Remember, if in doubt, please reach out.
If you are experiencing dirty or discoloured water, it’s important to note that this is an issue separate to the presence of MIB and Geosmin and related taste and odour issues in our water supply.
Please stop use, seek further information on our dirty or discoloured water page for next steps to take, including reporting the issue to Council.
We are continuing to monitor the water quality in both Port Macquarie and Cowarra Dams to ensure public health is protected at all times.
Routine water quality testing of our drinking water through our NATA accredited Environmental Laboratory also continues to ensure that we provide safe potable water in line with the Australian Drinking Water Guidelines.
MIB and Geosmin cannot usually be removed without specific treatment processes. At present, our water infrastructure does not feature these options.
We are planning for the future, however, and the design of our new Cowarra Water Supply Scheme, scheduled to be operational in 2028 will have the option to employ the necessary treatment processes required to reduce the effects of MIB and Geosmin.
It is unclear how long the increased levels of MIB and Geosmin will last. Historically, as the water temperature comes down, the levels of the taste and odour compounds will decrease.
MIB and Geosmin are by far the most common compounds causing taste and odour events in source and drinking waters across the world.
Council monitors both Cowarra and Port Macquarie Dams routinely for these compounds.
Given MIB and Geosmin are compounds produced by certain types of micro-organisms, factors that contribute to increases in their presence will therefore potentially increase the concentration of MIB and Geosmin.
In aquatic environments, the major factors that influence growth of these micro-organisms are light conditions, temperature and the chemical composition of the water.
Council diligently and frequently monitors a range of water quality parameters including examining the water for a range of micro-organisms at our river intakes and within our dams. Our dams also have exclusion zones with no public access.
Our testing includes using online instruments, conducting physical testing and testing at National Association of Testing Authorities (NATA) Accredited Laboratories. Read more about our water testing here.
The historical data collated from our routine monitoring over many years shows a correlation between increased growth of certain micro-organsisms and the warmer weather. As the water temperatures decrease, the number of these micro-organisms also decreases.
Port Macquarie Hastings Council is committed to ensuring the long-term sustainability and efficiency of the region’s water infrastructure.
Anticipating the growing demand for our community's drinking water in the years ahead, we are proactively planning and have plans for expansion through the Cowarra Water Supply Scheme, expected to be operational in 2028.
We are committed to transparency and hold your safety and satisfaction as our priority. As such, we regularly share information on our website on our water testing facilities, water usage levels, dam levels and more. For a deeper dive into our water infrastructure, Council runs regular free behind-the-scenes tours of Cowarra Dam and the Wauchope Water Treatment Plant.
Visit here for upcoming tours and to secure your spot.
Yes it does. Routine water quality testing of our drinking water through our NATA accredited Environmental Laboratory ensures that we provide safe potable water in line with the Australian Drinking Water Guidelines.
No. The taste and odour occurrences happening now are due to the recent increased levels of the naturally occurring taste and odour compounds – Methylisoborneol (MIB) and Geosmin – in our water supply.
No. Routine water quality testing of our drinking water through our NATA accredited Environmental Laboratory ensures that we provide safe potable water in line with the Australian Drinking Water Guidelines, and in accordance with our water policy, and these measures and standards are being met.
Learn more about the steps to take if you encounter dirty or discoloured water here.