01
City Water System
Copenhagen’s water services are run by HOFOR, the Greater Copenhagen multi-utility, which supplies drinking water and drains wastewater and rainwater across eight municipalities. Within the city, HOFOR Vand København and HOFOR Spildevand København are the regulated companies, each with its own accounts and tariff. The City of Copenhagen is the majority owner, holding 73.59% of HOFOR’s water holding company and 61.37% of its wastewater holding company, and it adopts the city’s water, wastewater and climate-adaptation plans. BIOFOS, owned by 15 municipalities, treats Copenhagen’s wastewater at Lynetten and Damhusåen. Frederiksberg, enclosed by the city, has its own provider. The national Water Sector Supervisory Authority sets the utilities’ economic frameworks.
02
Resources & Supply
Copenhagen draws all its drinking water from groundwater. Wells across Eastern and Central Zealand feed seven regional waterworks, which treat it without chlorine. HOFOR produced 54.1 million m³ in 2025, and 31.6 million m³ was delivered in Copenhagen. There, household use averaged 98 litres a person a day and water loss was 5.8%.
The constraint is spare capacity, not network performance. HOFOR’s supply buffer was 11% in 2025, against a desired 20–30%. Contamination has forced cuts at eight of about 50 wellfields, and voluntary agreements protect less than a fifth of the areas that recharge the regional waterworks. In a June 2026 drought, HOFOR was producing at full capacity and asked customers to save water.
03
Wastewater & Stormwater
HOFOR collected 41.6 million m³ of wastewater across its eight municipalities in 2025 and sent 98.6% of it to treatment. In Copenhagen, the network includes just over 1,200 km of main sewers. BIOFOS treated 105 million m³ for about 1.25 million residents in 2025, and expects to need around 40% more capacity by 2045. On 13 November 2026 its board is due to choose between expanding the existing plants and moving Lynetten to Prøvestenen. Management recommends the move. HOFOR is also designing retention basins at Spangen and Utterslev Mose to cut overflows into local waters. Construction is expected to start in 2026 and 2027.
04
Investment & Resilience
HOFOR’s Copenhagen water and wastewater companies invested DKK 1,595 million in 2025, up from DKK 952 million in 2023, and forecast DKK 1,609 million for 2026. HOFOR is building or modernising eight waterworks. Regnemark is expected to deliver water in 2028, and permitting for Islev and Gørløse began in 2025.
Cloudburst protection is the other main programme. The Kalvebod Brygge tunnel is due in service for the 2027 season, and construction of the 10 km Svanemøllen tunnel has begun. After a change in national rules, the city expects only 59 of 242 planned surface projects to reach the Cloudburst Plan’s 100-year standard. A new climate adaptation strategy is being prepared.
05
Key Challenges
- Rebuilding the supply buffer from 11% towards the desired 20–30%.
- Protecting wellfields from PFAS and other contamination while voluntary agreements cover less than a fifth of recharge areas.
- Expanding metropolitan wastewater treatment by around 40% by 2045 while managing the projected rise in customer bills.
- Managing cloudburst risk as fewer planned projects can be built to the 100-year standard.