Most parts of the Greater Dublin area are to see reduced water pressure from Monday.
The restrictions are due to the lack of rainfall and will take effect between 10pm and 5am.
With no significant rain forecast, it is hoped the restrictions will help avoid widespread outages in the autumn.
Irish Water's Kate Gannon says customers should not lose supply.
She said: "Irish Water is introducing restrictions from 1pm to 5am in central Dublin and the surrounding areas from Monday night.
- Digital Desk