Some 94,500 customers of Irish Water, or 7 per cent of households, face water charges for excess usage in 2019, based on consumption trends for last year.

The Commission for Regulation of Utilities has set out how the Government should charge for excessive use of water by Irish households in its latest analysis.

In a report to Minister for Housing Eoghan Murphy, the commission found the average rate of demand to dwellings was 125,000 litres per year, and the estimated annual rate of demand by an individual was 47,000 litres per year. Estimated average incremental demand was 25,000 litres per year for each additional occupant above four in a dwelling.

Mr Murphy yesterday ratified the figures, which will inform a threshold that will apply in a new charging scenario. In addition to this threshold amount, a household with more than four occupants will receive an additional allowance amount of 25,000 litres for each person above four occupants.

Households where excessive water usage is due to medical needs will be eligible to apply to Irish Water for an exemption from payment of the charge, he confirmed.

Under new legislation, it is up to the Minister to set a threshold amount for water demand based on the commission’s figures, and Irish Water customers who use above the threshold may be charged for water demand above the threshold.

The commission is the economic regulator of Irish Water, the national water utility responsible for delivering and developing public water and waste-water services in the State. Its latest analysis confirms a disproportionate spread of demand across users, indicating that the highest users of water in Ireland use significant volumes.

The Minister will apply the multiplier of 1.7 to the commission’s average rate of demand at a dwelling. A charge for the volume of water used above the threshold would apply to about 7 per cent of 1.36 million domestic customers of Irish Water, according to the analysis. That 7 per cent of customers use about 31 per cent of all water provided by Irish Water.

Public consultation

Irish Water said “ultimately the approved charge will be a matter of Government policy, and Irish Water will implement that policy as directed”. It regarded this measure “as primarily enabling us to assist customers to conserve water and fix leaks”, a spokeswoman said.

The commission findings are based on Irish Water meter data from 2016, involving 475,000 households. The terms of excess usage charges will be subject to public consultation during 2018.

Although Irish Water customers who use amounts of water greater than the threshold will be charged for the excess, this will not take effect immediately. Irish Water shall inform a customer if the threshold amount has been exceeded in a 12-month period. It will not charge the customer during this period.

What level of charges will apply to an excessive user cannot be determined at this point, according to Irish Water.