During the initial stages of the NWSDB, from 1975 to 1990, provision of potable water supply to townships, villages and industrial estates was given more consideration. However, with the increase of water usage and land becoming inadequate for on site sanitation, emphasis was given for sewerage too during the last 10 years. At present, NWSDB maintains the sewerage systems in Kolonnawa, Dehiwela - Mt. Lavinia several NHDA housing schemes in GC area, Hantana and Kataragama. The CMC owns and maintains the Colombo City sewerage system. A pipe borne sewerage scheme has recently been commissioned for the coastal town of Hikkaduwa located 100 km South of Colombo. Wastewater collection, treatment and disposal systems of Katunayake, Seethawake, Biyagama and Koggala Investment Promotion Zones are maintained by the NWSDB on behalf of BOI. Treatment systems for Mawathagama, Polgahawela, Modarawila and Mirigama Investment Promotion zones are being constructed by the NWSDB at present.

A pipe borne sewerage project to minimize the environmental pollution of Kandy City center and surrounding area is to be implemented with Japanese assistance. Feasibility studies including Environmental Impact Assessment were already finalized including lands for pump stations and treatment plant. It is proposed to locate the treatment plant in a land belonging to the Agriculture Department, Peradeniya and discharge effluent after treatment to the Mahaweli Ganga.

A project was formulated recently with the assistance of Swedish Government for Ja Ela - Ekala and Moratuwa – Ratmalana Industrial and Residential areas. It is proposed to have a sewer network and a treatment plant at Ja Ela - Ekala while another treatment plant and a short sea outfall is proposed for Moratuwa - Ratmalana. A substantially large area is to be sewered in Moratuwa including the town and the University under the proposed project.

Projects to address the immediate rehabilitation needs of the Colombo city – Northern and Southern sewerage system are being implemented with the assistance of Danish and Austrian Governments. Respectively It is proposed to construct a new pump station at Madampitiya and to rehabilitate Peterson Lane pump station including rehabilitation of about 20 km of main sewer lines from Kollupitiya to Madampitiya under Northern project, where as new pumping station at Wellawatte and rehabilitation of about 9 km of sewer lines will be included in the Southern Project.

A water supply & sewerage project has been formulated for Kurunegala town and DANIDA mixed credit has been identified for funding. This project is in tendering stage at present.

The ADB has assisted to carry out a consultancy assignment to study the feasibility of Jaffna Peninsula Water supply & Sewerage Project. This study was completed this year. US government has provided funds to study sewerage requirements of coastal Town under Tsunami aristae.

The ADB has also funded the Greater Colombo Waste Water Management Sector Review to review the overall sewerage problem of Greater Colombo. The consultants mobilized in the latter part of 2005.

A pipe borne sewerage scheme is being formulated by the NWSDB for Sri Jayawardenepura Kotte, Capital City of Sri Lanka with the assistance of Chinese Government. Basic designs and project formulation are almost completed and it is expected to start construction in 2009 once contract negotiations are over.

Planning and Designs including preparation of tender documents have been completed for sewerage facilities in Tsunami Housing schemes located in Trincomalee, Ampara, Galle and Kalutara. Similar assignments are being carried out for Sri Jayawardenepura University, Havelock City, Ratmalana Tsunami Housing, Thelippalai Cancer Hospital and Ranala Housing Schemes.

The NWSDB imposed a sewerage service charge with effect from 01st April 2008 in all sewerage schemes maintained by the NWSDB. Presently, NWSDB maintains the sewerage systems of about 06 large housing schemes (Mattegoda, Soysapura, Jayawadanagama, Madddumagewatte, Raddolugama and Hantane) with a total of 10,000 housing units in addition to earlier mentioned sewerage schemes. Furthermore, foreign lending agencies were insisting on the introduction of a sewerage service charge to extend loan facilities for new sewerage projects. Imposition of a fee is required to cover the O&M costs of the existing systems as well as to gradually expand the sewerage facilities to other urban areas.