Irish Water has said it expects the regulator to take a definite decision on the discounts that will be applied to households on boil water notices before the end of this month.
Its Head of Communications Elizabeth Arnett said that, according to a draft decision published in August, a discount will be applied if drinking water is unfit for consumption in a household that has been on a boil water notice for longer than three months.
Speaking on RTÉ's Morning Ireland, Ms Arnett said this would amount to 50% off the net water bill.
It was already decided that people will be capped at the assessed charge or the average charge for their household and that there would be discounts for people who have a medical illness, she said.
In documentation sent out to the public, Irish Water asked that people indicate if they believe they would qualify.
Ms Arnett said: "You tick that box and we would send you out a subsequent form that you would fill in."
She also said the company must ask people for their PPS numbers, in order to ensure that water allowances go to the appropriate people.
People will not receive their allowances unless they provide their PPS numbers.
She said: "We cannot use PPS numbers unless we have the authority to do so ... We have been given the legislative basis to do so.
"We cannot use them except in the circumstances that have been designed, which is to ensure that people get the allowances they're entitled to."
Earlier in the month, the company confirmed a possible breach of data occurred after it sent information packs with the wrong names to over 6,000 customers.
Homeowners whose houses are not tied to public sewage schemes will face drastically reduced water charges when they are levied from next January.
The new charges are based on drinking water in and waste water out of households.
Those with private septic tank systems will not have to pay for water removal, meaning their bills will be reduced.
Ms Arnett said that having a septic tank means water bills will be halved.
Around 500,000 households in Ireland have their own septic tanks for dealing with waste water.
Elsewhere, Fianna Fáil leader Micheál Martin has told the Dáil that there was mounting anxiety about water charges.
He told Tánaiste Joan Burton that it was incomprehensible that people with boil water notices would have to pay.
Mr Martin said the charging by volume was regressive and there was no link to ability to pay.
Ms Burton said Fianna Fáil had proposed flat charges for water.
She said it was being rather cynical since it had agreed flat charges with the International Monetary Fund.
