Clean and tasty drinking water – the waterworks of Østerby

City of Aarhus

About Author

Arhus is Denmark’s 2nd largest city and the  financial centre of the Central Denmark Region. The city has a catchment area of 1.2 million people within a one-hour travel range and is well connected to Copenhagen and Hamburg.

See partner

All citizens of Aarhus should have access to naturally clean groundwater, also in the future. Protecting the groundwater against pesticides requires hard work as well as close dialogue with – and supervision of – the agricultural sector. It is essential that the citizens have drinking water that is both tasty and of high quality. The drinking water is partly delivered by 29 private water service providers and partly by waterworks owned by the company Aarhus Water.

Aarhus Water’s waterworks deliver clean drinking water from 100 water wells. The company controls 10 waterworks, one watertower and 10 elevated storage tanks. The drinking water is distributed within the city by a 1,500 kilometers long main water pipe and 46,355 service pipes.

Controlled and supervised from Aarhus Water’s headquarters, all ten waterworks are unmanned. The CRS solution monitor all elements from well, waterworks and storage tanks. Recently the water pipes are included in the CRS solution, by monitoring distribution wells in the pipe system. The CRS system and the distribution wells are an effective tool to monitor for potential pollution, pressure, flow and water loss.The loss of mains water is very low, only around 5-7 % and despite the high water quality and secure distribution, a liter of water costs less than EUR 0.50.

The architects behind Østerby Waterworks are Cubo Architects. In 2002, the Østerby Waterworks received an award from the City of Aarhus for its architectural design.  The new building is “pushed” into the small hill on the western side of the site. Consequently, the water treatment – which cannot be exposed to daylight – is situated in the western side of the building, thus “cutting itself into the hill”. The offices, the instruction room, etc. are situated in the eastern side of the building, thus facing the light and the panoramic view.

The building composition and the materials chosen narrate a story of simplicity, cleanness and highly prioritized hygiene. The plant consists of concrete, poured in situ, stainless steel, coated zinc, and unhewn stone.

On average, each inhabitant in Aarhus has a daily water consumption of 115 litres.

The water treatment at Østerby Waterworks undergoes a simple treatment. The treatment of the groundwater is a to step process: Aeration and filtering. The aeration is atmospheric air that is blown bottom up through the water, and thereby oxidizing iron and manganese, and removing sulfide dioxide.  After aeration, the water goes through a gravitation sand filter, that removes the oxidized iron and manganese. After treatment, the water is pumped from the waterworks to the storage tanks.

Did you like this solution?

City of Aarhus
  • 19 Solutions
  • 12 News
Primary contact
Aarhus Vand
+45 8947 1000


Looking for our logo?

Find it in the State of Green Toolbox together with loads of materials to help you promote Denmark’s green solutions abroad.
Visit toolbox