Householders and businesses are braced for the risk of further flash floods and crippling clean up costs as weather forecasters tonight warned of more heavy rain.
Cork and Belfast bore the brunt of the first swathe of freak downpours as storm drains and gulleys proved useless against deluges over seven hours.
At the height of disruption more than 10,000 homes in the Cork area and 1,000 in the North suffered black outs.
Flood damage hit hundreds of homes and businesses in the Cork suburb of Douglas with the village streets inundated by several feet of water, the shopping centre and well known local pubs and restaurants worst hit.
Local concerns centred on whether a storm culvert designed to cope with a major flooding incident was able to wash away the rain water.
Douglas had suffered the heaviest rain in the country in a short blast yesterday evening – 49.1mm.
Some of the other hardest hit areas included Clonakilty, where the Farla river was close to bursting its banks most of the day with the town cut off for hours, and Glanmire where some homes in one estate ended up in five feet of water.
Nearer the city, the southside suffered the most with homes in Greenmount, Bishopstown, the Viaduct, Turner’s Cross, Ballyphehane and Togher badly damaged.
Mallow avoided danger as the flood waters on the Blackwater peaked in the afternoon while the warning systems for flooding on the River Bandon in Bandon town were on yellow most of the day, high status.
“The council is continually monitoring all wastewater and water service facilities to ensure continued service but at present all are operating as normal,” a spokesman for Cork County Council said.
“The council are also in contact with the ESB regarding power issues at pumping stations and routing emergency generating equipment.”
Met Eireann said 50mm of rain fell in a three-hour period across Cork on to already saturated ground – three times the average June total has fallen in Cork this month.
According to official records the city’s airport has average rain of 67.7mm in June – today it is 230.8mm – more than three times higher.
Dublin Airport is two and a half times over the June average of 55.8mm.
Forecasters warned that rain will be very heavy this evening, especially across the Midlands, Leinster and in Ulster. There will be a chance of thunderstorms and hail, along with the risk of further spot flooding, it said.
Rain is also forecast to be heavy overnight across the south and east of the country, with a chance of thundery downpours and further flooding in the far south. Tomorrow will see more showers mixed with good dry spells and the weekend is forecast to be dry.
City Council bosses said pre-emptive action helped reduce the impact of the flash floods which left more than a dozen areas under water. Emergency services in the city received 128 calls for help following floods, including 45 callers needing direct rapid response.
Worst-hit in the city were a significant number of properties, both business and residential, in Blackpool Village and Watercourse Road in the early hours of the morning.
Elsewhere, the council said localised flooding was reported on the Old Kinsale Road near the business park, Sarsfield Road roundabout, Monaghan Road, Centre Park Road and Turner’s Cross.
Up to a metre of water was reported on the main streets of Douglas village with 10,000 customers blacked out at around 8.30am when an electricity sub-station went down.
Most homes were quickly restored and by lunchtime all of Douglas was reconnected while the rest of the day was spent trying to reconnect 700 in Clonakilty and 200 in Bandon and other pockets in the county.