Northern Ireland Water was overwhelmed by more than a million contacts from the public at the height of the burst pipes crisis, a Stormont committee was told today.
Officials from the state company received 600,000 phone calls in three days at the height of the episode
and was sent 10,000 emails, while its website was bombarded by half a million hits.
But Northern Ireland Water (NIW) chief executive Laurence MacKenzie, who resigned last night and officially leaves office tomorrow, was condemned for failing to meet the committee over his organisation's handling of the emergency.
Chairman of the Regional Development Committee Fred Cobain said Mr MacKenzie had a duty to account for his
company's actions after Arctic weather conditions crippled the region's water supply system, and the public calls for help were mishandled.
"I have to say the committee is deeply disappointed that we don't have the chief executive here, who is still the chief executive of Northern Ireland Water," said Mr Cobain.
"He should have been here. This is a huge issue, not just for this committee and the Assembly, but for the thousands of people who have suffered. He has a responsibility to those people. As far as we are concerned he should have been and he is not."
Mr MacKenzie has “on his own initiative” tendered his resignation and it has been accepted by the board of the company, it was announced early this morning.
His resignation will come into effect from midnight tomorrow. It will be up to the Sinn Fein Minister of Regional Development Conor Murphy to decide whether to approve the terms and conditions of his severance package.
The position of Mr MacKenzie, who was on a salary of £182,000, became untenable because of the mishandling of the North's water crisis that left 40,000 householders in Northern Ireland without water over the Christmas period.
His position was further undermined when the Minister Mr Murphy this week said "everyone's confidence in the operation of NIW has been shaken very badly" by how the company failed to cope over the Christmas freezing conditions and subsequent thaw.
His resignation was announced after midnight last night after a meeting of the board of NI Water that lasted nine hours. No details were given on his severance package other than it was "consistent with his contract and entitlements".
The board has recommended that Trevor Haslett, director of engineering procurement at NI Water be appointed as acting chief executive.
In a statement this morning, NI Water said it wished to "acknowledge the significant contribution made by Mr MacKenzie to develop open and transparent governance arrangements within NI Water in line with public service obligations and the efficiencies achieved within price control demands".
"The board would like to take this opportunity to wish Mr. MacKenzie well in the future," it added.
Mr Murphy meanwhile is planning an investigation into the Christmas water crisis. He is to propose at today's meeting of the Northern Executive that an external review be conducted by the Northern Ireland Authority for Utility Regulation.
"The Regulator is an established independent body which already has a statutory duty to regulate water and sewerage services. It is therefore suitably qualified and has access to the range of required industry skills and expertise to conduct the review," he said yesterday evening.
Mr Murphy said he was advised that the earliest the Regulator could report would be the end of February. "But it will, during the investigation, where feasible, identify any short term recommendations for the company to consider and improve performance, should such weather conditions recur this winter," he added.
Pressure was also maintained on Mr Murphy to resign over the water shortages. DUP MP Gregory Campbell and Mr Cobain said that the minister should quit his post.
Mr Cobain is today chairing a meeting of the Regional Development Assembly committee at Stormont which is examining how and why the water problems were so severe.
Sinn Féin Assembly member Carál Ni Chuilín said there was no question of Mr Murphy resigning and that the party was fully behind the Minister.
"Mr MacKenzie is responsible for the operations of NIW, operations which failed to deal with the recent thaw. His company fell well below the standards expected by the public," she said. Ms Ni Chuilín said there should be no "pay off from the public purse" to Mr MacKenzie.
NI Water said earlier yesterday that there were no properties yesterday that were without supply. It said there were 33 properties that had intermittent supply due to low pressure on high ground. It again appealed to businesses and householders to check premises for any damage to pipes.
Additional reporting by PA