Is the tap water in Oslo hard, and does it contain chlorine or fluoride?
Hardness, limescale, chlorine and fluoride in Oslo's drinking water.
Short answer
Oslo's tap water is soft and is disinfected with UV light instead of chlorine, and no fluoride is added to drinking water anywhere in Norway. The City of Oslo gives a hardness of about 2.5 °dH, so you do not need to add salt to the dishwasher. About 90% of the water comes from the Oset treatment plant.
Why
- The City of Oslo measures a hardness of 1.9–2.3 °dH in water from Maridalsvannet and 2.2–2.8 °dH from Elvåga, with 13.3–20.0 mg of calcium per litre.
- According to the city's water statistics, all drinking water passes through hygienic barriers, and UV light is used instead of chlorine to disinfect it.
- Store medisinske leksikon writes that drinking water is not fluoridated in Norway or its neighbouring countries, and that public waterworks usually supply surface water low in fluoride.
Details
Oslo has two water treatment plants, at Skullerud and at Oset by Maridalsvannet. The city says the water is of high quality and safe to drink unless it issues a warning, but its colour, smell or taste can change for periods. The pH is 7.37–7.55 for water from Maridalsvannet and 7.70–8.00 for water from Elvåga.
Tip
Skip the dishwasher salt in Oslo: the city says it is not needed because the water is soft.
What may differ
Private wells are different: Store medisinske leksikon notes that some private boreholes can contain several ppm of fluoride, while the limit for public waterworks is 1.5 ppm.
People also ask
- How hard is the water in Oslo?
- Is there limescale in Oslo tap water?
- Is fluoride added to tap water in Norway?
Sources
- City of Oslo: Drinking water qualityChecked at:
- City of Oslo: Water production and consumptionChecked at:
- Store medisinske leksikon: FluoridationChecked at:
Information checked on 15 October 2026.
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