The east coast and Dublin Metropolitan area were under water last night as sustained heavy rain yesterday and overnight has caused serious flooding and will not ease until this afternoon.
Several minor roads in north Dublin, Kildare and Meath were closed last night, and many homes remained under threat of localised flooding.
The Meteorological Service also warned of further flooding, with the danger of rivers such as the Dodder and the Dargle bursting their banks.
The highest level of rainfall was recorded in the Dublin area where yesterday afternoon 53mm or just over two inches of rain had fallen during the previous 24 hours. As much as an extra 20 millimetres was expected to fall overnight.
The worse hit areas were Dublin, Meath and the east coastal regions of Wexford and Waterford. The least affected areas were Cork and Kerry.
Mr Vincent O'Shea, of the Meteorological Service, said the ground was already damp from previous rain before the heavy downpours yesterday, and local flooding was expected to continue today.
"Although it is not breaking any records, well over two inches of rain is a lot, and the rivers are in full flood so localised flooding can be expected again today, with the danger of the rivers bursting their banks."
He said it would be early this afternoon before the rain eased off. By this evening it would clear, and be mainly dry tomorrow and at the weekend.
Mr Douglas Hyde, of Fingal County Council, in north Co Dublin, said they experienced significant difficulties due to the downpour. At the M50 Blanchardstown interchange, traffic was diverted up ramps.
"Minor roads such as Hearse Road, Donabate, Estuary Road at Swords, The Strawberry Beds and the Old Airport Road are all closed due to flooding," Mr Hyde told The Irish Times.
"We've had several requests from householders in the Dublin 15 area for sandbags so we've called in the Civil Defence to assist us," said Mr Hyde.
All Fingal County Council staff were out helping with the sandbags last night. Over 10 people were manning emergency telephones "until they stop ringing", according to Mr Hyde.
Late night shopping was also disrupted when electricity supplies were cut off in parts of Dublin city centre.
Mr Kevin McDermott, of the ESB, confirmed that up to 100 businesses had their electricity cut off when a sub-station was flooded in Duke Street, off Grafton Street. This affected shops and restaurants on Dawson Street and St Stephen's Green. Power was restored to 70 of the businesses by 6.30 p.m. and Mr McDermott expected power to be returned to the remaining outlets by midnight.
In Meath an elderly couple were evacuated from their flooded home in Batterstown. Several roads in Dunboyne were impassable, with many cars abandoned in the middle of floods. There were no reported casualties.
Meath County Council was out in force sandbagging homes in the Beechdale area.
"Fifty or 60 houses are threatened with overflow from the river that feeds into the Tolka" said Civil Defence officer Mr Michael Fitzsimmons. "It's the same as a couple of years ago. It's pretty bad now but we're assessing people's needs on a house to house basis" he told The Irish Times.
Several people were rescued from the tops of their cars in Kildare yesterday evening.
Five people were rescued from their stranded cars on the Clane Road out of Kilcock. A motorist was taken from a flooded car in Kellystown, near Intel, while emergency services rescued another person from the top of a car outside Confey GAA club in Leixlip. None of the rescued sustained any injuries.
The Dunboyne-Maynooth road was closed due to flooding, while Kildare Fire Brigade closed the Kellystown Bridge. Water had been pouring both above and below it all day, leading to fears for its collapse.
Fire brigades from Leixlip, Maynooth and Edenderry were busy from 10.30 a.m. yesterday pumping water from flooded homes. Kildare Civil Defence delivered sandbags to those unable to collect them from Maynooth Council yard.
The N4 road near Kilcock was the worst affected area in Kildare. All fire brigades, county council personnel and the Civil Defence assisted at the scene.
Swords fire service rescuing children stranded at Balheary Educate Together school after it was cut off by floods near Swords, north Co Dublin.