HAMBURG WASSER

About the Utility

HAMBURG WASSER brings together two companies that stand side by side under unified management: Hamburger Wasserwerke GmbH, which supplies drinking water, and Hamburger Stadtentwässerung AöR, which collects and treats wastewater. The Free and Hanseatic City of Hamburg owns 100 percent of both, holding the waterworks company through its municipal holding HGV and the wastewater institution directly under the Stadtentwässerungsgesetz. The group supplied around 2.3 million people with drinking water in 2024. Its subsidiary CONSULAQUA carries operator expertise abroad, and the group holds half of Holsteiner Wasser. An externally verified EMAS environmental management system has been validated every year since 2008.

Water System

Hamburg’s drinking water comes exclusively from groundwater, abstracted at depths between 20 and 429 metres and treated at 16 waterworks. Rather than build new works, the company is raising maximum daily output to 500,000 cubic metres within existing plants, including new filters installed at Stellingen during operation. Securing abstraction rights is the sharper constraint. The Nordheide wellfields supply around 300,000 residents, yet only a weaker, more easily revoked “gehobene Erlaubnis” was granted, and the appeal still awaits a hearing. Network losses remain low, and PFAS results sit below both current and forthcoming drinking-water limits.

Wastewater System

Hamburger Stadtentwässerung runs the sewer network and four treatment plants, led by Klärwerk Hamburg, which met every condition of its discharge permit in 2025. Treated volumes follow the weather: after a record-wet hydrological year with repeated extreme cloudbursts, they fell back sharply in 2025. Combined sewer overflows are a recurring pressure, with 49 of 131 outfalls operating in 2025. The plant generates more electricity than it consumes, and the company has welcomed the recast EU directive that makes manufacturers of problem substances share responsibility for removing them.

Investment & Priorities

Capital spending rose at the water company and eased slightly at the wastewater company in 2025, with sludge incineration, energy recovery and waterworks capacity among the priorities. Financing is moving onto a green footing. A Green Finance Framework adopted in June 2024 underpinned a first green loan with UniCredit in July 2025, and a €70 million green Schuldschein loan has been allocated in full to the VERA II sludge-incineration project. Wastewater fees and water prices both rose in 2025.

Sustainability & Resilience

HAMBURG WASSER aims to supply itself entirely with renewable electricity by 2030 and already covers most of its energy use from renewable sources. Its treatment plant is becoming a resource-recovery site, with the VERA II sludge-incineration line, the HPHOR phosphorus-recovery plant and Germany’s largest wastewater heat pump. With the environment authority, it runs the RISA sponge-city initiative and produced Hamburg’s heavy-rainfall hazard map, as extreme weather becomes more frequent. The work earned the German Sustainability Award 2025 in the water-supply category.

Key Challenges

1. Securing long-term groundwater abstraction rights, including the contested Nordheide permit.
2. Raising waterworks output to 500,000 cubic metres a day without building new works.
3. Managing combined sewer overflows and stormwater as extreme rainfall becomes more frequent.
4. Delivering VERA II and phosphorus recovery before the 2029 sludge and phosphorus rules apply.
5. Reaching full renewable electricity self-supply by 2030.

Major Projects