PUB is the national water agency and it manages Singapore's water supply, water catchment and sewerage in an integrated way. PUB is responsible for managing the whole water cycle, from sourcing to the collection, purification and supply of drinking water, to the treatment of used water and its reclamation into NEWater, as well as the drainage of stormwater. Leveraging on technology, PUB has put in place a reliable water supply system known as the Four National Taps. Water reclamation (or NEWater) and desalination make up two of the four water sources, besides water from local catchments and imported water. To ensure the sustainability of Singapore's water supply, PUB continuously invests in R & D to find new sources of water and to produce and treat water cost-efficiently.