Northern Ireland Water is under pressure from politicians to improve its performance before public confidence in the company evaporates.

As revealed in the Belfast Telegraph yesterday, 5,400 non-domestic customers have been overcharged — about half of them by more than £50 — and a further 2,400 have not paid enough.

Stormont’s regional development committee, which monitors the company, has been examining the faulty data on which the thousands of incorrect charges were based.

“This is just the latest in a line of errors that have been caused by NI Water. It was only last year that NI Water announced that it had made a mistake in calculating water costs meaning that household bills would be £30 higher,” Alliance MLA Kieran McCarthy said.

“NI Water must improve their billing services immediately to ensure that no more errors occur.

“If these types of mistakes are not eradicated then some people may lose confidence in the company.

“With the current economic downturn I am sure that businesses did not need the problem of being overcharged, money that could have been better spent on shoring up their businesses.”

And SDLP MLA Tommy Gallagher said: “The whole Northern Ireland Water charging system is a total disaster.

“The present administration at Stormont went ahead and brought in charges for businesses and community facilities in 2008 without having any ideas who owned certain properties and who they needed to charge.

“Many of the premises brought in didn’t have meters then and still don’t have any fitted now. Therefore, many of these bills are the results of estimates and guesswork.”

Mr Gallagher said he had recently received an Assembly reply from Regional Development Minister Conor Murphy revealing that almost £410,000 had been charged to church and church properties in the past financial year — a figure that could now be open to scrutiny. “I have no doubt many of the mistakes that have arose have been due to this flawed system and further believe many more mistakes will continue until there is reform and diligence brought to it,” he said.

NI Water’s director of finance and regulation, Ronan Larkin, said he did not believe it was a situation in which “heads must roll”.

“In terms of being open and being honest and trusthworthy, we have always taken a stance to do that,” he said.

Mr Larkin said in many cases there was no point in spending money on persuing people who owed relatively small amounts.

Today’s Viewpoint, Page 28