The Head of Customer Operations with Irish Water has said some supplies are moving into drought and critical drought conditions.
Yvonne Harris said data was gathered before the long weekend, adding that technical teams will gather more information this week but it is highly likely that a water conservation order will be issued this week.
Such a move, she said, would be to protect supplies for consumers and would be weather dependent.
Overall 16 drinking water schemes are already in drought with a further 38 at risk.
Ms Harris said demand on hot days is soaring beyond previous levels and there was demand for an additional demand of 30 million litres of water- the equivalent of an additional 200,000 people in Dublin - while similar trends were reported around the country.
She appealed to people to conserve supply and only use it for necessary purposes because water for hand washing and hygiene during the current Covid-19 crisis is essential for everyone.
Ms Harris added that while there has been a decrease in commercial demand, large industry continues to use water.
In addition domestic demand represents two thirds of usage and, she said, even before the dry spell of weather, demand had increased among domestic usage.
Nighttime water restrictions for Westmeath
Water restrictions are being imposed tonight in Co Westmeath for customers in Coole, Castlepollard, Delvin, Clonmellon, Raharney and surrounding areas to safeguard the supply.
Irish Water and Westmeath County Council said the move is required to allow reservoirs to refill following high demand so that daytime water supply can be maintained.
The restrictions will be in place from 10 o'clock tonight until 6 o'clock tomorrow morning.
Customers in these areas are asked to be mindful of how they use water but to continue to follow public health guidelines on hand washing.