There are calls for Lidl to pull plans to sell pools for the back garden next week.
The pools need up to 7,500 litres of water but the supermarket chain says they contain a filter so they do not need to be drained and filled every time they are used.
However, Irish Water is urging people to conserve supplies during the heatwave.
Green Party leader Eamon Ryan says the system is already under pressure and he wants Lidl to play its part.
"It's very tempting with this warm weather. Wouldn't it be lovely to be lounging around in a pool?
"But we're all running short on water. We've got to be careful. We could go into a long dry spell and if we do this summer, we're going to really have to be very careful how we use it [water].
"So I think Lidl should play their part. I think they should pull those pools. It's not the right time to be doing it."
A status yellow high-temperature warning was issued by Met Éireann yesterday and is in place until Friday with temperatures set to hit 30 degrees this week.
- Digital Desk
