the results of the survey. The utility indicated at the time that 70% of its customers had continuous supply, that 63% had meters and that 97% of meters were in working condition. However, the survey indicated that 42% had continuous supply, that 76% were metered and that only 77% of meters were in working condition. Groundwater overexploitation 82% of the city's water supply is abstracted from groundwater through 577 deep tube wells, while four relatively small surface water treatment plants provide the remaining 18%. Groundwater levels are dropping at two to three metres every year. The city's water table has sunk by 50 metres in the past four decades and the closest underground water is now over 60 meters below ground level. The Asian Development Bank estimated in 2007 that by 2015 a severe supply shortage would occur if the utility did not reduce groundwater abstraction. Nevertheless, DWASA announced in 2012 that it will develop a new wellfield with 46 wells providing 150,000 cubic meters of water per day at a cost of US$63 million, of which US$45 million will be financed by the government of South Korea. Inadequate sanitation In Dhaka, nearly one third of domestic effluents does not receive any kind of treatment. About 38% of the population is covered by a sewerage system. There is one wastewater treatment plant with a capacity of 120,000 m³ per day. About 30% of the population uses conventional septic tanks and another 15% uses bucket and pit latrines. During the rainy season, sewage overflows are common. Other issues Low tariffs and cost recovery Residents of Dhaka enjoy one of the lowest water tariffs in the world. The Executive Head of DWASA lists provision of water at low cost as one of the achievements of the utility. However, low revenues limit the utility's capacity to make a higher contribution to investments. According to DWASA's official website, in November 2011 the metered residential tariff was 6.6 Taka (US$0.09) per cubic meter. For households with sewer connections the tariff was 15.5 Taka (US$0.21) per cubic meter. Unmetered residential water connections were billed 128 Takas (US$1.72) per month. The commercial, industrial and institutional tariffs are more than three times higher. Total revenues were the equivalent of about US$70 million per annum in 2010 and, according to DWASA management, cover about 25% more than the operating costs of the utility (operating ratio of 0.79). However, a