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Drinking water quality

Taste and odour of drinking water

The water tastes and smells different.  What has caused this?

Seasonal conditions can result in increased algal activity in both Port Macquarie and Cowarra Dams.   Contributing factors that can typically increase algal activity are when water levels are lower and elevated temperatures. 

Increased algal activity can result in the presence of the compounds geosmin and methylisoborneol (MIB). These compounds produce an earthy and/or musty taste and odour in the water and only need to be present at extremely low levels to affect the water quality (10 nanograms/litre which is equivelant to one drop in a household pool). Routine water quality monitoring includes the testing for these compounds.

Are there any health risks?

These naturally occurring compounds are non-toxic and do not represent any public health risks.  The presence of these taste and odour compounds result primarily in aesthetic water quality issues.  Council adheres to the advice set in the Australian Drinking Water Guidelines regarding drinking water quality.

What is Council doing?

Council continues to manage nutrient levels in both Port Macquarie and Cowarra Dams to limit algal growth.  Source water for the dams is from the Hastings River where stringent extraction parameters are in place including limits on nutrients. This management practice limits nutrient inputs into the dams. Water stored in both dams is constantly turned over (mixed) which maintains constant temperature and water quality throughout the storage at all depths and further reduces the likelihood of algal activity. Ongoing water quality monitoring ensures public health is protected at all times.  

Water from the Hastings River and our stored drinking water is regularly tested at stations located throughout the catchment to ensure quality is maintained, and appropriate steps are taken when environmental and seasonal factors cause minor imbalances.

For more information, contact Council’s Customer Service Centre on (02) 6581 8111 or email council@pmhc.nsw.gov.au

Water Hardness

The ‘hardness’ of water is something that is of interest when it comes to new appliances.  Often new washing machines or dishwashers have specific settings for various levels of water hardness.  As a guide, water with less than 60mg/litre is considered ‘soft’, up to 200mg/litre is ‘good quality’, between 200-500mg/litre is considered ‘hard’, and more than 500mg/litre is ‘very hard’.

Port Macquarie-Hastings water supply has a target hardness of 40 - 60mg/litres, and is therefore considered ‘soft’.

Guidelines for Water Safety

The National Health and Medical Research Council (NH&MRC) produces the Australian Drinking Water Guidelines (ADWG) to provide advice to water suppliers.  The Guidelines recommend safe limits for various compounds found in drinking water, including blue-green algae toxins.  

Alert Levels Framework (ALF) for Drinking Water is also available to provide advice to water suppliers in the monitoring and management of the development of potentially toxic blue-green algae blooms in the water supply.

 

This page was last updated on: 16 October 2020