Responsibilities are as follows:
1. Plan, control and construct the sewer system and pump wells
2. Plan, control and clean up the drains
3. Plan, control and process the production of manhole covers and pipe maintenance equipment. Everyday awareness to seal, change the manhole cover and maintain the drainage system
4. Plan, control and conduct flood / tide protection dike and structure
5. Plan, control and action to prevent and mitigate flood problems in the sewer and pumping in control polder system.
6. Plan, survey, inspect and improve the design of drainage systems.
7. Perform other related duties or assigned.

The division consists of 5 sections as follows:
1. General Administration Section
1. Correspondence and general administration
2. Administration and coordination work
3. Procurement
4. Staff and discipline work
5. Finance and budget
6. Public relations
7. Supervision and facilitate of office premises and vehicles
8. Perform other related duties or assigned

2. The Drainage System Maintenance Section 1
1. Planning and Cleaning the drainage system in the main streets.
2. Plan and Mitigate flood due to heavy rainfall, high sea tide and northern runoff in collaboration with government agencies under Drainage and Sewerage Department and related agencies
3. Control and reduce the water level in the drainage structures at the end of the pipe before entering the canal. Keep water in the sewer at low level, so that the drain pipe can handle the rainfall.
4. Build sandbags line along the Chao Phraya River/King‘s dike to protect water inflow, etc.
5. Inspect the construction of public utilities to protect affect the drainage system
6. Resolve complaints about flooding in the main street
7. Support Construction of drainage facilities to optimize drainage system
8. Monitoring and management of pumping wells to fix drainage problems.
9. Perform other related duties or assigned. This section is responsible for 25 areas including Dusit Phayathai, Ratchathewi, Bang Sue, Din Daeng, Huay Kwang, Chatuchak, Bang Khen, Sai Mai, Don Muang, Lak Si, Bueng Kum, Wang Thonglang, Lad Phrao, Bang Kapi, Min Buri, Khlong Sam Wa, Nong Chok, Saphan Sung, Khannayao, Suan Luang Prawet, Lat Krabang, Bangna and Phra Khanong.

3. Drainage System Maintenance Section 2
Drain System Maintenance 2 has the same authority as the Drainage System maintenance 1 section, but responsible for the area of 25 districts: Phra Nakhon, Pom Prap Sattrupai, Samphanthawong, Pathumwan, Bang Rak, Yannawa, Sathorn, Bang Kho Laem, Wattana, Klong San, Thonburi, Chom Thong, Thung Khru, Bang Khun Thian, Bang Bon Rat Burana, Bang Phlat, Bangkok Noi, Bangkok Yai, Talingchan, Bang Khae, Phasi Charoen, Nong Khaem and Thawi Watthana

4. Drainage System Engineering Section
1. Study, analyze, plan and solve flood problems in main roads.
2. Plan and divide areas into polder system for managing/increasing drainage efficiency
3. Conduct survey, design, cost estimate of drainage and related structures construction for improving, repairing and enhancing the drainage efficiency of Bangkok.
4. Inspect and approval of drainage system construction according to design specification and contract in order to resolve flooding effectively
5. Consultation and advice on drainage system to internal departments and external agencies, both public and private sector
6. Consider and allowing the connection to public pipes in the main road.
7. Consider and allowing of dismantling drain system due to the construction of the mass transit system and underground utilities, etc. to minimize affect to efficiency of drainage
8. Perform other related duties or assigned

5. Drainage System Repair Section
1. Manufacture and supply of manhole covers, drainage system pipes and sewer equipment, repair and improvement of damaged sewer.
2. Seal and replace the damaged manhole cover
3. Increase the efficiency of the drainage system to resolve the urgent flood problem by construction of the new pumping station, manhole with weir or flap gates, etc.
4. Support various agencies in solving flooding problems.
5. Conduct surveys, design, cost estimates the self-constructed drainage systems to improve, repair and increase drainage efficiency by using machines, materials and labor of this section
6. Perform other related duties or assigned.