Bangkok is the capital and most populated city of Thailand. The city is situated on the bank of Chao Phraya River and provides a benefit to open seas. With an area of 1570 square kilometers and has population of approximately 11,518,930 (October 2013). Bangkok has a tropical wet and dry climate which is under the influence of the South Asian monsoon system. Bangkok lies in the humid tropics and hot last throughout the year.
The main sources of drinking water are both surface water and groundwater in Bangkok. The Metropolitan Waterworks Authority (MWA) supplies estimated 91% of total demand to residential, industrial and commercial sectors using surface water withdrawn from Chao Phraya River and the remaining 9% is extracted from deep well. However, the surface water is highly polluted in Thailand due to untreated domestic sewage, industrial wastewater and solid hazardous wastes, much of the water in Bangkok and the wider Chao Phraya river basin has been classified as ‘deteriorated’ by the United Nation.
In the remote areas of Bangkok, water supply systems are mainly based on groundwater system. The largest source of groundwater is in the lower central plain surrounding Bangkok which is used to meet the water demands of the region. Bangkok has 8 confined aquifers and most of the groundwater extractions used is Phra Pradaeng, Nakhon Luang and Nonthaburi aquifers. These aquifers are mostly used because of their higher productivity, accessibility and good quality of water. However, exploitation of other deeper aquifers is also trending in recent years mostly from industrial use.