PLANS to construct more than 1,000 social homes have been put on hold because Northern Ireland's outdated water system needs a £2.5billion overhaul.
According to Ulster Unionist MLA Roy Beggs, this is just the tip of the iceberg, with developments in more than 100 areas in danger because they cannot be linked to the existing sewage network, which is at full capacity.
Communities Minister and Sinn Fein MLA Deirdre Hargey has also expressed major concerns that the perilous situation could result in some of society's most vulnerable people being left homeless.
Eight proposed schemes, totalling more than 1,000 properties, are affected by the sewage fiasco, along with several planned private developments, including the £500million Tribeca project in Belfast city centre.
The Housing Executive told Sunday Life the delay had hit planned social housing schemes at the Gasworks, Hannahstown, Hope Street and Shore Road in Belfast, Sean Dolan GAA in Derry, Clonavon and St Patrick's in Ballymena, and Dunluce Street in Larne.
Mr Beggs, whose Assembly questions uncovered the setback, said: "What it basically comes down to is, no drains, no cranes. Northern Ireland Water has advised that additional sewage from new developments in over 100 areas cannot be linked to the existing sewage network for treatment as systems are at full capacity. This has been curtailing new private developments.
"Now the Communities Minister has advised that over 1,000 urgently needed social houses are also at risk. Clearly we need to re-prioritise spending."
Mr Beggs called on the Executive to commit funds to urgently update the sewage system instead of pouring more public money into "flagship schemes" such as the redevelopment of Casement Park and the A5 road upgrade.
He added: "Choices must be made because many families will remain homeless unless the Executive takes decisions to prioritise and enable capital investment in vital sewerage infrastructure.
"The scale of capital funding and the delivery schedule of flagship schemes should be reassessed, given the real pressures on wastewater treatment."
In a written response to an Assembly question from Mr Beggs, Communities Minister Deirdre Hargey spoke of her concern at how the outdated sewage system could lead to lengthy delays in the construction of 1,000 badly needed new social homes.
She said: "The potential implications for the development of social housing schemes because of the current issues affecting the water/sewage infrastructure is a concern for me, particularly given the increasing levels of housing stress.
"I understand that presently there are around nine schemes, totalling more than 1,000 units programmed over a number of years, at risk.
"I have asked the Housing Executive to carry out a detailed analysis of the areas of housing need that may be impacted by the water infrastructure issues."
Ms Hargey explained that officials from her department were working with Infrastructure Minister and SDLP MLA Nichola Mallon, who she said wanted to "explore potential solutions to what is a growing problem".
Northern Ireland Water chairman Dr Len O'Hagan previously warned that it would take £2.5billion to bring sewage services up to scratch.
He said: "To put it bluntly, the system is getting ready to burst at the seams.
"Due to historic underfunding, many of our wastewater treatment works are at or are rapidly approaching full capacity.
"This means we can't accept new connections for new developments, which will be severely curtailed.
"Inadequate funding also leads to inadequate environmental protections. No drains means no cranes.
"To remain fit for purpose, we calculate that we need £2.5billion, including £1billion to address wastewater, flooding and drainage problems in Belfast alone."