Overnight water restrictions are to be imposed in most areas across the country as authorities struggle to repair leaks and meet demand.
Officials have appealed for the public to be patient as emergency teams continue to work round the clock fixing burst mains and pipes in almost every county.
The Department of the Environment warned that reduced supply is inevitable as city and county councils battle to meet abnormal demand.
Gerry Galvin, principal adviser for water services, urged householders to use as little water as possible.
"I would appeal to people to be patient during this very difficult time as local authorities attempt to identify and repair the many leaks that have occurred in the public system," he said. "We have just come through some of the coldest weather in decades and the resultant thaw has caused very serious disruption to the water system nationwide."
Standpipes and water tankers have been dispatched to areas where the supplies have been worst affected.
Mr Galvin urged householders and businesses to heed the request from local authorities to conserve water, notify leaks visible on the streets and check unoccupied premises.
All city and county council water supply plants are on full production, the Department said, and it warned night-time restrictions are in place to replenish reservoirs.
Dublin City Council said its engineers still have a lot of work to do to stabilise the situation. Cork City Council said consumers may be facing temporary disruption, pressure fluctuations and temporary discolouration, but should receive a daily refill supply to properties.
Problems to supplies continue to be reported in counties Cork, Galway, Kerry, Kilkenny, Kildare, Laois, Sligo and Westmeath. It is feared full supply in most areas may not be restored until the new year.