In the past, when it was the Bangkok Municipality and the Greater Bangkok municipality. The agency responsible for canal maintenance and drainage cleansing was the Office of the Canal Dredging Operation Committee and the Public Cleansing Division. When Bangkok Metropolitan Administration was established in the year 2515 B.C., the Public Cleansing Division under the Public Work Department maintained drainage sewers, restoration of canals, and waste disposal. Later in the year 2517 B.C. according to Ministry of Interior Announcement, the Public Cleansing Division under Public Work Department was reorganized to be the Public Cleansing Department to serve in the water drainage work, collection and disposal of solid waste and night soil. In the year 2520 B.C. Department of Drainage and sewerage has been established in accordance with the government division decree and duties of the Bangkok Metropolitan Administration, issue dated 19 May 2520 B.C. separated from the Public Cleansing Department and to be responsible for the drainage, flood protection and waste water disposal.
Currently, the Drainage and Sewerage Department of has been reorganized its division structure and duties and responsibilities according to the 5- year capacity plan, consists of the following divisions:
1. Secretariat Office
2. Water Quality Management Office
3. Drainage System Development Office
4. Water Control Systems Office
5. Drainage System Division
6. Canal System Division
7. Mechanical Division
8. Drainage Information System Division
Mission of the agency
1. Create master plans and projects about the flood prevention system, drainage system and wastewater treatment system for Bangkok
2. Construction and maintenance of flood protection systems and the drainage system of Bangkok , consist of floodgate, pumping station, drainage tunnel , dam along the canal, water barrier lines and sewer pipes as well as supply and develop a water retention system or water banks.
3. Planning, controlling and drainage management, prevention and mitigation of flooding. Control of brackish water and drought problems in Bangkok.
4. Planning, controlling and carry out the maintenance of drainage, pump station, seal and replacement of the manhole cover. Production of pipes and covers to prevent and mitigate flood problems in the area
5. Dredging of canals to increase drainage efficiency of canals and water bodies. Including developing pleasant siding landscapes and preventing encroaching structures on the canal and other public water sources
6. Drainage line maintenance, collecting garbage, weeds and water hyacinth in canals, receiving ponds and public water sources
7. Water quality management in Bangkok area by monitoring, surveillance, inspection and controlling of water quality in public water sources. Including collecting wastewater from the source for treatment. Using appropriate and feasible technology to achieve water quality according to international standards
8. To be an information center for water management and telemetry system of Bangkok
9. It is a center of consultation cooperation, recommend and support academic information on Bangkok water management. Prevention and mitigation on flood problems, water quality and coastal erosion management
10. Supply, control, installation service Including repair and maintenance of water pumps, both electric and engine types, machinery, machine tools and vehicles
11. Perform other related duties or assigned.