Apart from the main Laboratory in Mzuzu, there are satellite laboratories in all NRWB Operation areas. The quality of the water in supply is ensured through a water quality monitoring (WQM) program. The establishment of sampling points is done based on quality control requirements at the treatment stage, and factors that determine the level of risk of recontamination in the distribution system.
The frequency of sampling of any control point is determined based on the vulnerability for recontamination. Laboratory analysis, database management and reporting of results is done in conformity with WHO guidelines. Several parameters are tested but for purposes of public awareness, the following key parameters shall be reported on: pH, colour, turbidity, Residual free chlorine and faecal coliform.