The government owned company has seen four chief executives at its helm since it was set up six years ago.
The last chief executive, Trevor Haslett, stepped down from his post at the end of August citing “personal reasons”.
Sarah Venning, who joined NI Water in April 2010 as director of customer service delivery is currently standing in as chief executive however, it is understood she did not apply for the new post.
An NI Water spokesperson said: “The competition for the appointment of the CEO for Northern Ireland Water Ltd is now complete, and unfortunately we are unable to make an appointment at this time.
“The Company has satisfactory interim arrangements in place which are continually under review, and we will shortly decide on a timetable to re run the competition.”
However, the Social Democratic and Labour Party (SDLP) spokesperson John Dallat described NI Water’s failure to hire a chief executive as ‘deeply disturbing’.
“NI Water has a history of drifting aimlessly in the past and against a background which brought no credit on the organisation or those then at the helm.
“We cannot have a repeat of that and we need to know why thousands of pounds in advertising for a new chief executive didn’t attract an individual of the calibre that is required to steer this organisation through a very difficult future,” he said.
The company has been marred by a number of failings at boardroom level since its creation in April 2007.
Haslet had been appointed acting chief executive in January 2011, after Laurence MacKenzie resigned over mishandling of a cold weather crisis that saw 450,000 lose their water supply.
Haslett threatened to step down in autumn 2011, reportedly due to dissatisfaction with his £130,000 salary, but stayed on.
In 2010 the then chairman Chris Mellor and three other board members were sacked amidst controversy on how the company was awarding contracts.
Northern Water’s first chief executive, Kathryn Bryan, resigned in 2008 after it emerged the company had miscalculated its projected income by £20 million.