Irish Water has confirmed that water in Dublin and Wicklow is safe to drink following complaints it has been tasting and smelling "musty" and "earthy" in recent weeks.
The utility company said specialist results received today, following ongoing testing of the raw water for the drinking water in Dún Laoghaire-Rathdown, Dublin city and north and east Wicklow areas, has indicated the presence of low levels of a naturally occurring substance called MIB (Methylisoborneol).
While MIB can result in some people detecting an earthy, musty smell and taste from their drinking water, it is not harmful to human health, Irish Water said.
MIB is a naturally occurring organic substance produced by algae found in lakes, rivers, streams and reservoirs.
Head of Asset Operations with Irish Water Tom Cuddy said: "Our primary focus is the protection of public health and we would like to reassure customers that the water coming from the drinking water plants serving Dublin and Wicklow is safe to drink.
"We understand the concerns raised by some customers in relation to the smell or taste of their drinking water.
"While the smell and taste can be unpleasant for some customers, MIB is not toxic or harmful and the water remains safe to drink.
"As a precaution, we have increased testing on these supplies and are keeping the situation under close review."
Seasonal increases in naturally occurring algae or bacteria in water sources can cause a rise in MIB above the taste and odour threshold for some people, Irish Water said.
It is impossible to predict the onset of an incidence of MIB or how long it will last, it added.
However, it will "likely be resolved in the short term as the current rain spell continues and the weather cools".
Irish Water will continue to keep this water supply under close review and will continue monitor levels of MIB in the water.
