The restrictions from 11pm to 7am are needed to maintain a daytime water supply in the region.
The company says heavy rainfall and impact on the river presented operational challenges at the water treatment plant, meanwhile continued high demand has not allowed reservoirs to return to normal levels.
Uisce Éireann say water levels will be reviewed every morning.
The areas impacted include Youghals, Cloheen, Ladys Cross, The Bypass Road, Cottage Road, Fernhill Road, The Miles, Tawnies Lower, Barrick Hill, Reenascreena, Santry North, Santry South, Inchinattin, Tullig, Carrigfadda, Glanbrack, Maulatallavally, Knocks, Threegneeves and Gortroe.
