Is our water safe to drink?

Yes!  Residents are advised that the City's drinking water is safe; this odour poses no health impact and is strictly aesthetic.  Drinking water in Hamilton is tested at the Environmental Laboratory on Woodward Avenue .  The Laboratory has been equipped with modern and sensitive instrumentation that allow the identification and quantification of trace amounts of organic and inorganic parameters in water.  Testing is conducted by the Environmental Laboratory on samples from the Water Treatment Plant and throughout the distribution system.

What causes the musty taste and odour in our drinking water?

The odour causing compounds are more prominent during extended warm temperatures throughout Lake Ontario .   Temperatures have recently reached 19 degrees Celsius and as a result we are experiencing increases in naturally occurring compounds which can create a musty odour or taste within the drinking water.  Two compounds called Geosmin and 2-Methylisoborneol (2-MIB) are responsible for a musty or earthy odour that is detectable by some persons in concentrations as low as a few parts per trillion (ppt).  One ppt is equivalent to 1 drop of water in 1,000 Olympic-sized swimming pools.

Where do these compounds come from?

Geosmin and MIB (2-methylisoborneol) are produced in aquatic environments by cyanobacteria (blue-green algae) or mould-like, filamentous bacteria called actinomycetes. Intensive testing of  Lake Ontario water during taste and odour events has confirmed that minute concentrations (measured in parts per trillion) of these compounds create the earthy/musty taste/odour.  Geosmin, the same substance that can be detected when rich soil is turned, is also found in some foods including beets.

When does the musty taste and odour occur?

Although occurrence frequencies are difficult to predict, a Geosmin peak generally occurs at the end of August each year. In 1998 and 1999 levels of over 100 nanograms per litre were found in this late summer peak. In 2000, 2001 and 2002 levels of only 10-25 nanograms per litre were found. It had been thought that taste and odour events only occurred periodically. We now understand that the events likely occur each year but the intensity can vary widely

How long will the musty taste and odour last?

Depending on the weather temperatures, these tastes and odours could persist in our drinking water for a couple of weeks.

Can these tastes and odours be removed by the Water Treatment Plant?

Hamilton 's Woodward Water Treatment plant uses  granular activated carbon (GAC)  to assist in providing quality drinking water.  The latest results indicate that GAC is reducing odour causing compounds by as much as 65% and all efforts continue to be made to further reduce the presence of these compounds in our drinking water.

Is there anything homeowners can do to reduce tastes and odours?

In-home water filtration systems that employ activated carbon can help to reduce or eliminate these tastes and odours.  If you purchase such a unit, please remember that it is very important to follow the manufacturer's instructions with respect to maintenance.  Cooling the water in your fridge can also help.

What research is being done to learn about the taste and odour in the drinking water?

The Western Basin of Lake Ontario is the source of drinking water for over 5 million Ontarians. In 1998 and 1999 the whole region was impacted by prolonged and intense taste and odour in that drinking water. Extremely low concentrations of a naturally occurring substance, Geosmin, was the cause.  Water utilities have taken effective action. They invested in control technologies at the water treatment plants and intensive research into the cause and control of taste and odour.

The Ontario Water Works Research Consortium (OWWRC) was formed in 1999. The consortium brings together all of the large municipalities on the western basin of lake Ontario   with federal government, provincial government and university researchers.

The OWWRC has proven to be a model of scientific cooperation among the levels of government. It has already yielded significant new information about the biological cause of taste and odour, the role of temperature, winds and currents and the frequency of taste and odour events. It is expected that the research may provide the utilities with improved early warning of events and contribute to control strategies. An active research program is underway again in 2004.