Every day Stockholm Vatten och Avfall produces 360,000 m³ of drinking water in the two water treatment works of Lovö and Norsborg, and distributes it to 1.4 million people in Stockholm.
The water is retrieved in Lake Mälaren. To maintain a high quality of drinking water, measures are continuously taken to protect the source of water supply; Lake Mälaren as well as the reserve water source Bornsjön.
Several analytical methods are used to prevent pollution, and samples are frequently taken to monitor the quality of the water. There are also regulations regarding what industries, farmers and private persons are allowed to do in the areas surrounding the water works.
Lake Bornsjön, the reserve water source, is today a restricted area and the work to protect the lake has been so successful that its water today matches drinking water quality without treatment.