Laboratory Services of National Water Supply and Drainage Board

National Water Supply and Drainage Board Laboratory services are structured as given bellow,

• Central Laboratory Services
• Regional Laboratories
• Plant Laboratories

Each laboratory is under the direction of a Chemist with technical coordination and consultation being provided by an Assistant General Manager (Laboratory Services).

Central Laboratory

Central Laboratory functions as the Center for Water Quality Control. It serves as monitor for the activities of all levels of laboratories.
The Central Laboratory Services implements its sampling and analytical schedule as initiated by the AGM (Laboratory Services). It engages mainly operational monitoring and verification monitoring of water quality, research programs and promotes training. It functions as an active laboratory in water (microbiological, chemical, physical and toxic) wastewater, water treatment chemicals (alum, hydrated lime, bleaching powder, polyaluminium chloride, powder activated carbon & polyacrylamide compounds) heavy metals, volatile organic compounds including pesticides and filter media disciplines. Central laboratory acts in an advisory capacity to process control and serve as the processing center for Analytical data to provide higher management levels in the organization.

Sri Lanka Accreditation Board for Conformity Assessment declares that Central laboratory of National Water Supply & Drainage Board having been found to comply with the accreditation criteria for testing laboratories as described in ISO / IEC 17025 : 2005, has been accredited as a testing laboratory under the field of chemical testing for water treatment chemicals; alum and hydrated lime.

Certificate of accreditation

Metal and Heavy metal analysis 

Atomic Absorption Spectroscopy (AAS)


Atomic absorption spectroscopy (AAS) is a spectroscopic analysis technique that determines the concentration of a particular element in a sample by atomizing the contents of the sample and measuring the absorbance of a wavelength specific to that particular element in the gaseous state.





This is emission mode of spectroscopy and it’s performed to identify and measure a range of chemical elements.






Microbiological Testing

Enumeration of algaes and cyano bacteria are being conducted under this section. In addition to that this is used to observe pathogens and other microbial organisms in wastewater and other water samples in critical situation.


Microbiological Laboratory

Total Coliform Escherichia coli test
Membrane filter method and Colilert method are used to detect and count of Escherichia coli and Coliform bacteria. (SLS 614:2013 / SLS 1461 part 1 section 1 and section 2)


Total Plate Count

Total Plate Count analysis is the calculation of the number of bacterial colonies present in the sample with dilution as needed.

Regional Laboratories

The regional laboratory functions as a field unit with the capability of performing routine microbiological and chemical analyses. The laboratory implements its sampling and analytical schedule initiated by the Regional Chemist. It is responsible for operational monitoring and verification monitoring by engaging with water safety plans to maintain to assure the water quality. An active quality assurance programme is maintained. In addition to that, certain water testing methods have been developed according to the regional water quality issues.

Plant Laboratories

This unit provides the basic data relative to those parameters specified by upper level laboratories. The water treatment plant officers maintain the selected sampling points throughout the system with the coordination of Chemist for the process control of water treatment process. These laboratories are mainly responsible in operational monitoring.