Water restrictions are being imposed because of the heat wave to prevent a drought.
Irish Water has introduced overnight shutdowns on water supply in parts of West Cork, Kerry, Galway, and Donegal – with more on the way.
Water supplies to homes in Stranorlar and Ballybofey, both in County Donegal, will be lowered from 10 p.m. to 9 a.m. in the coming days.
Customers in Galway may experience low water pressure and supply disruption in the next days in Tamplecross, Gurteen, Carrabane, Cahertinny, Caherhenryhoe, Attymon, and Kiltullagh.
Those living on Cape Clear, just off the Galway coast, will have no water from 8.30 pm until 7.30 am until further notice.
The authority is asking households across the country to be mindful of their water usage, with temperatures expected to reach 31 degrees again today.
37 water supply plants have been impacted by the hot and dry conditions, and a further 60 are being closely monitored.