01
City Water System
Hamburg is a city-state, so its environment authority, BUKEA, is also the state water authority, responsible for groundwater, water protection zones, flood risk and wastewater rules. A state enterprise, LSBG, maintains the dikes. Water services are run by HAMBURG WASSER, two city-owned companies under joint management: Hamburger Wasserwerke supplies drinking water, and Hamburger Stadtentwässerung collects and treats wastewater and stormwater. Together they form what the group describes as Germany’s second-largest public water and wastewater undertaking. Hamburger Wasserwerke supplies the city and 19 adjoining municipalities directly and sells water to ten resellers in surrounding districts, giving a supply area of 2.2 million inhabitants in 2025.
02
Resources & Supply
Hamburg’s drinking water is entirely groundwater, drawn from over 400 wells up to 428 metres deep and treated at 16 waterworks by aeration and filtration, with disinfection only where needed. About 63% of demand is met within Hamburg, 24% from Schleswig-Holstein and 13% from the Nordheide in Lower Saxony. Network losses are low, at 3.8% in 2025.
The constraint is resource headroom. Abstraction across the three states reached 125.3 million m³ in 2025, against an assessed usable yield of 129.9 million m³ a year. A March 2025 HAMBURG WASSER position paper reported a court challenge to the Nordheide permit, which granted less water than the utility requested. Daily supply peaked at about 390,000 m³ on 16 May 2024, after ten dry days.
03
Wastewater & Stormwater
Hamburger Stadtentwässerung treated 156.5 million m³ of wastewater and stormwater in 2025 at the Klärwerk Hamburg complex in the port, which handles Hamburg’s flows alongside three smaller plants in the wider region. About three-quarters of the city’s sewer network keeps rainwater separate from foul sewage. The remainder is combined, and in heavy rain it overflows to local waters in a controlled way. Several inner-city trunk sewers were built in brick between 1871 and 1904, and the “Alte Riesen” programme is now relining them using trenchless methods. The treatment plant is also an energy source, generating more electricity than it used in 2025.
04
Investment & Resilience
HAMBURG WASSER plans to invest €1.15 billion in networks, plant and new technology in 2025–2029. After mains bursts at Kollaustraße and the B73, it announced in June 2026 a programme to renew about 270 km of drinking-water mains by 2035. Delivery capacity is a constraint: Hamburger Stadtentwässerung invested €142.6 million in 2025 against a €193 million plan, held back by construction-market bottlenecks.
Flood defence is a city responsibility. Hamburg’s public flood-protection line runs for 103 km, the city invests €20–30 million a year in it, and its construction programme targets completion by 2050. A climate adaptation strategy adopted in February 2025 prioritises flood protection, heavy-rain precaution and blue-green infrastructure.
05
Key Challenges
- Keeping abstraction within assessed groundwater yield as the supply-area population is projected to exceed 2.4 million by 2050.
- Securing long-term abstraction rights in the Nordheide, which meets about 13% of Hamburg’s water demand.
- Renewing drinking-water mains and historic trunk sewers while construction-market capacity limits delivery.
- Managing heavy-rain overflows and storm-surge risk as intense rainfall becomes more frequent and sea levels are projected to rise.
