Homeowners living in the most expensive parts of the capital use far more water than the majority of households across the State.
Large houses with en-suite bathrooms and power showers appear to be driving up water consumption, new figures from the Central Statistics Office (CSO) suggest.
Nationally, each household consumes an average of 383 litres of water a day. Homeowners in Tipperary and Kerry use the highest amount on a county-by-county basis, at 430 litres.
However, a breakdown of Dublin postal districts tells a different tale.
An analysis of consumption based on metered usage showed homes in Dublin 4, Dublin 6, and Dublin 13 consume more water than anywhere else.
In Dublin 6, which includes Ranelagh, Rathmines and Rathgar, average daily consumption is 488 litres a day - more than 100 litres more than the average.
In Dublin 4, which includes Sandymount, Ballsbridge and Donnybrook, it is 459 litres, and in Dublin 13, which includes Sutton and Howth, it is 444 litres.
Properties in these areas tend to be family homes, bigger than the average and with large gardens, which may be boosting consumption. They may also be suffering from leaks that have not been repaired.
Conversely, consumption is lowest in Dublin 2, where household sizes are smaller and many people live in apartments.
The CSO noted thousands of households are using vast quantities of water every day.
Only 0.3pc of all metered homes - nearly 2,200 - consume 12pc of all treated water produced across the year.
The figure stands at 10.8 million cubic metres - or almost 11 billion litres of water. These homes use at least 10,000 litres a day.
The Domestic Metered Public Water Consumption 2015 report also suggested that, if the Government proceeds with a recommendation from the Dail Committee on the Future Funding of Domestic Water Services to impose a charge for excess use, around 66,000 households would be hit.
The committee said each person in the State consumed 133 litres of water a day. The CSO says the average home is occupied by 2.75 people, meaning average consumption is 621 litres a household.
The metering report said 66,595 households consume 600 litres or more a day, and these could be hit with an excess charge.
More tan 26,200 households use 1,000 litres or more a day.
This data is based on meter readings supplied by Irish Water.
The number of domestic water meters in January 2015 was 519,781, and this increased to 764,319 by December 2015.
The CSO said it could not supply data for Dublin 17 and Dublin 24 due to the "relatively small number of meters" that had been installed.
These areas were among those most opposed to charges, and where protests against metering were held.