Irish Water has started work on a €500m project to supply Dublin with water from the River Shannon.
It is seeking tenders for a survey specialist to examine the water quality at Lough Derg and the Parteen Basin, where the water will be sourced.
When completed, around 350 million litres a day will come from Shannon to serve Dublin drinking water needs for the next 70 years.
It is believed Irish Water will submit a planning application at the end of 2015.