"Our assistance will help the government make water and sanitation services higher quality, cost- effective, and sustainable."
Fan said the sewer network suffers from frequent collapses and blockages. Colombo's storm water drains, some of which were constructed during the British colonial period, overflow during a heavy shower putting roads under water and blocking traffic.
Critics say Sri Lanka's post independent rulers, backed by an urban intelligentsia steeped in rural nationalism, have engaged in an anti-urbanization drive against the aspirations of their citizens, instead of going back to the villages and reversing urbanization themselves.
Rulers of East Asian nations on the other hand have facilitated the natural desires of socializing humans to gather in large cities and move out of agriculture into more gainful work that employs their brains instead of brawn.
Critics say rules of China and Vietnam in particular have bowed to the aspirations of their citizens in a big way in the last two decades.India, which started to give increasing economic freedoms to citizens from 1991, has seen sweeping urbanization, through infrastructure is creaking under the demand.
Sri Lanka's current administration has started to upgrade city infrastructure.
Meanwhile the ADB said its 300 million dollar loans will have tranches targeted at different aspects of a 400 million Us dollar state program to expand water and sanitation in the greater Colombo area.
The first tranche of 84 million US dollars will focus on cutting water losses at state-run National Water Supply Drainage Board, which is suffering losses due to so-called 'non-revenue' water.
Each year the water agency is estimated to lose 13 million US dollars worth water.
The ADB said the program aims to make 24 hours a day water available throughout greater Colombo by 2020 with a focus on improving services in underserved areas, cut water losses from 50 percent to 20 percent by 2020 and expand sewer network coverage to 100 percent.
ADB money will be used to repair and replace water transmission and distribution pipes and pumps, install high quality meters, and implement network mapping and leakage controls.
