The union representing Irish Water employees has said workers will resist any efforts to terminate or change their conditions of employment.
SIPTU's Adrian Kane said it has "made it abundantly clear" to political leaders that workers will not accept any reduction in terms and conditions of employment or any redundancies "that may arise from any reconfiguration" of the organisation.
Speaking on RTÉ's News At One, he said 60 people are directly employed in billing at Irish Water, including billing for commercial water rates, which will continue.
Mr Kane said there may be room for redeployment of staff, but said it is pre-emptive to discuss such options.
Charging for excessive use and water waste, he said, would "surely continue" under any regime the Commission of Inquiry would consider.
Mr Kane said that SIPTU has been consistently of the view that Irish Water should remain in public ownership.
The most effective way to build a 21st century water infrastructure for the State was through a single public utility, he said.
Water infrastructure 'old and crumbling'
The Director General of Engineers Ireland has said Ireland's water infrastructure has been inadequately maintained for many years and requires significant investment.
Speaking on RTÉ’s Morning Ireland, Caroline Spillane said that decades of under investment means that the system is unable to meet demand.
She said that while the local authorities have done a good job with the resources available to them, a single utility would have given Ireland an opportunity to have long-term planning on a national level.
Ireland's water system poses public health and environmental risks, she said.
"Almost half of our treated water isn't even reaching our pipes.
"The water supply to over 700,000 people is at risk of contamination every single day.
"We have about 20,000 people right now on boil water notices.
"Our infrastructure is old and crumbling. We have raw sewage being pumped into our rivers and waterways.
"We have 180,000 properties at risk from contamination from lead pipes and the European Commission has a case against Ireland over failure to protect our rivers and coastal ways," she added.
