IRISH Water has lifted a Boil Water Notice for around 3,000 of the 9,500 people in the areas of Shanagarry and to the south and east of Midleton.
However, the Boil Water Notice, which has been in place since November 27, 2019, remains in place for all other areas in the Whitegate Public Water Supply.
It has been possible to lift the restriction in these specific areas following works to redirect water supplies from other sources.
The Boil Water Notice was put in place for the entire Whitegate public water supply as a precautionary measure following issues with the treatment process caused by an increase in turbidity in the raw water supplying the treatment plant.
Neil Smyth, Irish Water's operations lead for Co Cork, says: "We fully appreciate the difficulty and inconvenience that a Boil Water Notice causes in the community.
"By re-routing water supplies from other areas not affected by this notice, we are now in a position to remove the Boil Water Notice for approximately 3,000 people.
"Their water is now being supplied from the Midleton and Cloyne Public Water Supplies and we are satisfied, following consultation with the HSE, that the water in these areas is now safe to drink.
"It is important to stress, however, that the Boil Water Notice remains in place for approximately 6,500 people outside these specific areas.
"We are continuing to work with our partners in Cork County Council to restore normal production at the Kilva Water Treatment Plant.
"This involves works to enhance the treatment process which will help us ensure that water leaving the plant is fully compliant. Further testing will follow, in consultation with the HSE, to ensure that it is safe to remove the notice."