The surveillance and quality control of public water supplies are vital prerequisites for the protection of public health.
In practice however, the two activities of surveillance and quality control are often confused and inadequately implemented, especially in the case of surveillance in less developed countries. The two are clearly distinguished by the World Health Organization
‘In general, it is the responsibility of the local water authority to ensure that the water it produces meets the quality defined in drinking water standards. However, the surveillance function (ie a policing function on behalf of the public to oversee operations and ensure the reliability and safety of drinking water) is best conducted in a separate agency (whether national, state, provincial or local). Although these two functions are complementary, experience suggests that they are better carried out in separate agencies because of the conflicting priorities that exist when both functions are combined’.
As a distinct activity, surveillance has been defined as ‘the continuous, vigilant, public health assessment and overview of the safety and acceptability of drinking water services’
Traditionally, surveillance has been linked to monitoring of water quality, although it is clear from the above definition that it is a far broader activity, concerned with all aspects of water supply which may influence health, including both quality and accessibility. Support for the establishment of a water supply surveillance programme by the Ministiy of Health of Peru was provided by the United Kingdom Overseas Development Administration between 1985 and 1990. This largely took the form of technical assistance and the provision of equipment. Particular emphasis was placed on training, Institutional dcvelopment, the formulation and implementation of methods for surveillance, and promotion of remedial measures.
The Programme was designated as one of three WHO demonstration projects for water supply surveillance together with smaller projects in Indonesia and Zambia. Within Peru, the Pan-American Centre for Sanitary Engineering and Environmental Sciences (CEPISPAHO/ WHO) provided support and an institutional base from which to promote replication in Latin America and the Caribbean.