Geosmin and MIB

Geosmin and Methyl-Isoborneol (MIB) are naturally occurring compounds that have a very strong, earthy taste and odour. Geosmin can be detected by human noses at very low levels.

Hunter Water routinely monitors for Geosmin and MIB in the water supply. These compounds are generally present in drinking water, however not at noticeable levels.

Generally, Geosmin becomes an aesthetic issue for customers when levels are in the range of 20-30 nanograms (one millionth of a milligram) per litre, but some people who are particularly sensitive may notice it at levels above 10.

What are the Effects of Geosmin and MIB?

Geosmin and MIB produce a musty, earthy smell and taste in drinking water, however are not harmful at levels present in drinking water.

What Causes Increased Levels of Geosmin and MIB?

Some kinds of algae and bacteria present in dams naturally produce Geosmin and MIB. Increased concentrations of these microorganisms can cause an increase in Geosmin and MIB concentrations above the taste and odour threshold.

What Can be Done About Geosmin and MIB?

Geosmin and MIB can not be removed from water using normal treatment processes.

During times of increased geosmin and MIB levels, Hunter Water may reduce the amount of water drawn from the affected water source.