Overflows at the Mutton Island Waste Water Treatment Plant on Monday evening and Tuesday morning, following the exceptional heavy rainfall over the Bank Holiday weekend has led to a ban on swimming at Grattan Road beach.
The prohibition was issued by the Galway City Council on Tuesday "as a precaution", while advisory notices of possible pollution were also posted at beaches in Salthill.
Bathing water samples were carried out in Salthill, at Grattan Road and at Ballyloughane beach on Wednesday morning and the council will advise of further actions that might be required on receipt of results of the sampling.
A spokesperson for City Hall said: "The overflows at Mutton Island are a very uncommon event and the last such incident occurred during Storm Eleanor in January 2018. Galway City Council had put in place prior warning notices at several city beaches over the last weekend in anticipation of the heavy rain that had been forecast. The council will keep the public informed as needed over coming days."