My Water Has a Taste & Odour

It is not possible to predict the onset of an incidence of geosmin, or how long it will last. Geosmin compounds have been shown to remain in lakes and reservoirs for days to months. It is expected the concentration of geosmin will fluctuate during the coming weeks/months, however, we are not able to predict the duration based on historical trends.

A list of geosmin concentrations in the treated water dating back to January 2017 can be found on this page.

Geosmin was most recently detected on October 28, 2019 at a concentration of 12 ng/l in the treated water. To put this into context, the general threshold for human detection is about 15 nanograms per litre (15 nanograms per litre = 15 parts per trillion). However some people can detect geosmin in drinking water at concentrations as low as 5 nanograms per liter. This explains why some residents notice the taste and odour, while others do not.

Geosmin is not removed by conventional water treatment processes used by Halifax Water at the Pockwock water treatment facility.

There are several proven treatment technologies for removing geosmin from drinking water including granular or powdered activated carbon; oxidation with ozone or advanced oxidation processes (AOPs); biofiltration; or some combination of each. The actual technology used at a specific plant is highly dependent on the chemistry of the source water.

With the source water changes that we have been seeing over the past few years, including increased algal activity, Halifax Water is developing a long-term capital plan that will ensure the treatment process is able to continue to provide high quality, safe drinking water, while also being robust enough to adapt to future source water conditions, including the presence of geosmin. Halifax Water has been working with both consultants and researchers at Dalhousie University, through work at both the bench and pilot scale to study potential treatment options that will be incorporated into the long-term capital plan.

The implementation of a multi-million dollar engineered solution could take several years and involve continued research, pre-design, detailed design, regulatory approval, and construction activities.