Open dumps not only cause environmental degradation but also cause losses to the country’s economy. Due to ignorance by many, it has become the most common method of disposal of Municipal Solid Waste (MSW) in the country. Meethotamulla dump site is one such open dump site located in Kolonnawa Municipality in Western Province of Sri Lanka. Until its collapse in April 2017, 850 metric tons of MSW was dumped daily and around 1000 households were directly affected around the dumpsite. The externalities of open dumping are not directly observed in the market, thus often underestimated. Hence, the main objective of the study was to estimate the total cost of major externalities caused by an open dumpsite. A household survey was conducted using a ...