Irish Water and Wicklow County Council say the notice is a precautionary measure following a failure in the treatment process.
Irish Water drinking water compliance and operational experts are working with colleagues in Wicklow County Council to resolve this situation as soon as possible.
In the meantime, all customers of this supply are advised to boil water before use until further notice.
The areas affected include Ballinaclash, Avoca and Ballymoneen.
Meanwhile a do not consume notice put in place last Christmas eve for residents in Kiltegan, is still in force affecting around 300 residents.