The major duty of the company is distribution of clean drinking water and hygienic collection of urban sewage of Tehran province. Although this province, with an area of 12981 square kilometers, comprises 1.2% of the country’s area, it has 14 million inhabitants which 92% of them are urban, and this equals to 20% of Iran’s population. 13 cities and 54 towns lie within Tehran province and it comprises 44% of the country’s industries. Moreover, Tehran is the capital of Iran and the most sensitive political centers are within this province, which increases the importance of providing services for the company twofold. Tehran province Water and Wastewater Company carries its duties through its sub companies including six water and wastewater companies in Tehran (ABFA companies 1-6) and some others in east, southwest and southeast of the province, cities and towns of western Tehran, company of water supply and water and wastewater treatment company and also sewage company of Tehran. Considering precipitation, Tehran province has an annual of 230 mm, which places it among the provinces with average rainfall. The amount of renewable water in the province during a year is 4.2 billion cubic meters, which considering its high population, has a very low per capita renewable resources. Currently, this number is 350 cubic meters per individual, which equals one sixth of per capita renewable water in the country. However, according to global standards, if this amount is lower than 500 cubic meters in a year, it is a sign of intense water crisis.