The Water and Sewerage Company Inc. (WASCO), has a rich history dating back to 1965, when it was established as the Central Water Authority (CWA) under the Ministry of Health. Constituted under the Water Authority Act No 24 of 1964, its initial mandate was to oversee the provision and distribution of potable water, as well as the conservation and augmentation of water resources with a focus on preserving and protecting water catchments. 

Prior to the formation of the CWA in 1965, the Castries City Council (CCC) was responsible for the supply and distribution of water to the community. Historical records from the CCC indicate that pipe-borne water was available in Castries as far back as 1848. Before that period, residents relied on rivers, streams and ponds for their water needs. By 1915, most towns and villages across Saint Lucia were benefiting from some form of basic pipe-borne water supply. 

In 1984, The Government of Saint Lucia passed legislation transforming the CWA into a statutory corporation with the expanded responsibility for managing both water and sewerage services. As a result, CWA was renamed The Water and Sewerage Authority (WASA), overseen by a Board of Directors under the purview of the then Ministry of Communications, Transport and Public Utilities. During this period, WASA undertook several significant infrastructural projects, including constructing the John Compton Dam which continues to serve the northern portion of the island. 

The Sarot Treatment Plant, established in 1972, featured the installation of a one-million-gallon water storage tank at Ciceron, which was linked to the Cap Estate residential development by a 14-inch Ductile Iron Transmission Main.  This facility was pivotal in enhancing water distribution to consumers from Castries to Cap Estate. However, in 1993, the commissioning of the state-of-the-art Thomas R. Theobalds Treatment Plant in Ciceron heralded a new era in the island's water distribution capabilities. The modern plant continues to serve as the primary source of potable water for Saint Lucia's northern region. 

In October 1999, the water sector in Saint Lucia underwent a significant transformation with the establishment of the Water and Sewerage Company Inc. (WASCO) which is 100% Government-owned. Incorporated under the Companies Act, WASCO operates under the regulatory framework of the Water and Sewerage Act (2004) which further defines its responsibilities. This restructuring was designed to enhance the management, distribution and long-term sustainability of the island's water and wastewater services. 

Today, WASCO operates as a public utility under the purview of the Ministry of Infrastructure, Ports, Transport, Physical Development, and Urban Renewal. The Company continues to prioritise the responsible management of the island's water resources for future generations and is dedicated to the ongoing improvement of its infrastructure, investing in modernisation and expansion projects that enhance service delivery, increase efficiency and meet the growing demands of a developing population. Through these efforts, WASCO strives to maintain high standards of water quality, accessibility, and environmental stewardship, to support the well-being of all consumers.