Uisce Éireann has confirmed it is extending the hosepipe bans currently in place for the Kells-Oldcastle area in Co Meath, Mullingar in Co Westmeath and Milford, Co Donegal for an additional four weeks until 13 October.
This is because water levels in the local lakes supplying these areas remain critically low.
Those three Water Conservation Orders were first imposed four months ago on 6 May following a sharp drop in water levels.
Cumulative rainfall in the previous seven months had been 28% below normal.
Lough Owel, which supplies the Mullingar Public Water Supply, was at its lowest level in 50 years.
Similarly, Lough Colmcille, which supplies Milford in Donegal, and Lough Bane, which supplies Kells-Oldcastle in Co Meath, were also at historically low levels.
These lakes are fed by underground springs or have small catchments and can take considerably longer to recharge than other sources even with wetter weather conditions.
Uisce Éireann said continued monitoring shows that despite recent rainfall, the long-term effects of a dry autumn, winter and spring - followed by the warmest summer on record - have left these water sources significantly depleted still.
The water levels remain critically low and that is why it needs to extend the hosepipe bans in those three areas.
The company said its operational teams have worked intensively throughout the summer to maintain water supply by repairing leaks, managing pressure in the network, and tankering water directly into reservoirs.
"These efforts, together with communities supporting our conservation appeals, have helped to stabilise supply, but the risk of water supply disruption remains high," it said in a statement.
Speaking on RTÉ's Morning Ireland, Uisce Éireann’s Head of Water Operations Margaret Attridge said heavy rainfall is good for replenishing water levels, but it can be a slow process.
"We tracked the profile of the lakes every year and these lakes normally start to recover around mid-October," she said.
"We are having rainfall, which is good, so the ground is getting saturated which is good, and it'll just take time to make its way to fill these lakes."
Ms Attridge added: "Based on the profile of recovery in other years, we would expect to be lifting at towards the middle of October."
Meanwhile, Water Conservation Orders currently in place for counties Tipperary, Waterford, Wexford and Cork will lapse on 16 September and will not be extended according to the statement.
Increased rainfall and stabilising demand for water in these areas have reduced the critical risk to these water sources.
Uisce Éireann said it would like to acknowledge and thank the public for their continued support in conserving water and reporting leaks.
However, it said it remains critically important that everyone continues to do their bit to conserve water.
Mairéad Conlon, Asset Strategy Senior Manager at Uisce Éireann, said: "We know the public has made a huge effort over the summer to reduce their water use, and we're very grateful for that.
"But even where hosepipe bans are being lifted, it's important that people continue to use water wisely.
"The situation remains stark in several parts of the country following the warmest summer on record, and even though we are seeing a return to cooler, wetter weather, it will take several weeks or even months for those sources to recover."
