Irish Water has confirmed that although water demand went down at the start of October, it had returned to regular levels just a fortnight later.

The news raises questions about whether water charges will result in any drop in water usage - which had previously been presented as a hallmark of the government's water plan.

The data provided to Today FM by Irish Water relates to usage for the Dublin region, including neighbouring counties.

It shows a significant fall in in daily water production and demand around October 1st when charges originally kicked in, under the initial regime which has since been abandoned and replaced.

However, within a fortnight, the data shows that water use had returned to previous levels.

A spokeswoman said other factors might have influenced the usage of water around that time - like the mild weather - which meant fewer leaks because pipes do not freeze, and higher rainfall which meant farms did not need to use mains water.

But given that the data refers to Dublin, where agricultural use would be lower, the figures could suggest that even when charges were at their original higher rates, households were not likely to conserve much water if they could.

Announcing the reformed package of water charges last week, Environment Minister Alan Kelly said many households would be eligible for discounts on their water bills if they could cut their usage by 10% to 15%.

But documents given to TDs by Irish Water, while the previous regime was in place, showed that Irish Water itself only projected a 6% fall on water use as a result of metering and a change in customer mindset.