Procurement agency the Crown Commercial Service chose Castle Water as its recommended water supplier when it ran a second aggregation on behalf of public sector clients last month.
The new collective action, carried out in October, consolidated the requirements of 155 organisations across the public sector.
CCS said on average, customers stood to save 4-10% on retail charges by switching to the supplier it had recommended, Castle.
The agency brought the largest public sector water framework agreement to the UK market in April 2017. Castle has already won considerable public sector business through CCS’ first bulk tender.
Castle Water chief executive John Reynolds OBE said: “This recommendation will enable Castle Water to deliver immediate savings with high service standards to additional customers through the Crown Commercial Service framework.”