Local authorities in Dublin say water supplies will be greatly reduced, and cut in some cases, between 7pm and 7am over the coming nights.
The decision is being taken to conserve supplies, which have fallen due to leaks and householders leaving taps running.
Met Éireann is forecasting further snow this afternoon in east Leinster and parts of south east Munster, with temperatures falling to -9C tonight.
Motorists are again being warned of treacherous driving conditions with very icy roads and freezing fog nationwide.
Michael Phillips - from Dublin City Council - said there is more detail about what areas will be affected by the cuts to water supplies on local authority websites.