Irish Water predicts it will need to invest a minimum of €13bn to address deficits in the country's water infrastructure.
In a submission to the Commission for Energy Regulation, Irish Water outlines its investment plan and states the €13bn figure is the "minimum total capital requirement".
In its submission, seen by RTÉ's Prime Time, Irish Water concedes that "it is clear there will not be sufficient funding available to deliver everything that is needed in the near term".
This evening Prime Time reported on several failings in terms of water treatment.
The programme filmed human faeces on the water front in Rush, Co Dublin. 70% of the towns sewerage is pumped, untreated, directly into the sea.
A spokesperson for Irish Water told RTÉ that a solution is being considered to deal with the pollution, but will not be in place until 2020.
In its submission to the CER Irish Water says its previous estimate of 58,000kms of water mains has now been increased to 63,000kms, the increase was noted as a result of "better asset data".
The document also outlines how some activities have been deferred, such as full water sampling and upskilling local authority staff to help optimise the operation of treatment plants around the country.
It says the activities were deferred in order to meet "regulatory allowances"
Irish Water and the issue of water charges were discussed today during talks between Fine Gael and Fianna Fáil and will also be addressed tomorrow when talks resume.
