Irish Water's confirmed plans are in place to introduce excess water charges from next year.
A spokesperson says "the clock will start" on excess charging from next January - but bills won't be issued until at least July 2019.
The utility says a public consultation is to be carried out to determine what constitutes excess usage.
In a statement, Irish Water says: "The Water Charges Plan clarifies that there will be no charges for water services for domestic customers in 2018; provides that excess use charges will apply from 2019; advises that detail regarding excess use charge levels, commencement dates and associated rules and processes will be agreed with the Minister and the CRU and provided in a later version of the Water Charges Plan".
"Irish Water will implement this Government policy as directed and sees the policy on charging for excess usage as primarily a policy that will enable us to assist customers to conserve water and fix leaks."
But Solidarity TD Paul Murphy says the plans will face huge opposition.
"What lies between Irish Water's plan and the reality of water charges is the fact that water charges are still politically toxic, that water charges face mass opposition - which could again become mass protest opposition".