IRISH WATER HAS said that tap water in Dublin and Wicklow is safe to drink after customers complained of an “earthy” taste and smell.

Complaints about the quality of the drinking water in Dun Laoghaire-Rathdown, Dublin City and North and East Wicklow were made by customers in recent weeks. The areas are served by the Vartry Water Treatment Plant.

Irish Water carried out a microbiological and chemical analysis of the raw water for the drinking water in the areas as a result. 

It said the tests have indicated the presence of low levels of a naturally occurring substance called MIB (Methylisoborneol).

MIB is a naturally occurring organic substance produced by algae found in lakes, rivers, streams and reservoirs. While it can result in some people detecting an earthy, musty smell and taste from their drinking water, it is not harmful to human health.

The substance can be smelled at very low concentrations, and seasonal increases in naturally occurring algae or bacteria in water sources can cause a rise in the substance 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, but it will likely be resolved in the short term as the current rain spell continues and the weather cools.

It said it will continue to keep this water supply under close review and will continue monitor for levels of MIB in the water.

According to the World Health Organisation Guidelines for Drinking-water Quality, MIB has no public health significance.

Speaking about the detection of MIB in the drinking water, Tom Cuddy, Head of Asset Operations with Irish Water 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,” head of asset operations with Irish Water Tom Cuddy said.

“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,” he said.

“As a precaution, we have increased testing on these supplies and are keeping the situation under close review.”

Further information on MIB and drinking water quality can be found on Irish Water’s website.

Customers with queries or concerns about the quality of their drinking water can contact the Irish Water customer care helpline on 1800 278 278 or via Twitter.