01
City Water System
Amsterdam’s water services are divided between two public bodies that separated on 1 January 2026, after two decades of joint operation. Stichting Watermaatschappij Amsterdam, still trading as Waternet, supplies drinking water to Amsterdam and nearby communities including Amstelveen and Diemen, and manages the city’s sewers, urban surface water and groundwater under municipal mandate. The city owns the drinking water task. Waterschap Amstel, Gooi en Vecht, the regional water authority, treats wastewater and manages flood defences, water levels and water quality across 20 municipalities, large parts of which lie below sea level. National oversight rests with the Human Environment and Transport Inspectorate, advised on tariffs by the competition authority ACM.
02
Resources & Supply
Amsterdam’s drinking water comes from two source systems outside the city. In the west, Rhine water from the Lekkanaal at Nieuwegein is pumped through 302 km of bulk mains to the Amsterdamse Waterleidingduinen, filtered through dune sand and treated at Leiduin; Waternet says the dunes purify 66% of the city’s drinking water. In the east, seepage water from the Bethunepolder, topped up from the Amsterdam-Rijnkanaal, is held in the Loenderveense Plas and treated at Weesperkarspel.
Waternet’s 2024 regional action plan says regular capacity of 95 million m³ a year is enough until 2030, but that housing, economic growth and climate change will push demand higher. In August 2025 the province raised the dune abstraction ceiling.
03
Wastewater & Stormwater
Amsterdam’s wastewater is treated by the water authority, which treated 122 million m³ in 2025 and removes about 90% of pollution, meeting legal requirements. Its plants double as energy assets: with new wind turbines at the Amsterdam-West plant, the authority generated 117% of the energy it used in 2025. It is also adding ozone and activated-carbon treatment to remove medicine residues, aiming to cover all its plants by 2035.
Within the city, Waternet runs sewers and stormwater for the municipality under the Omgevingsprogramma Riolering 2022–2027, which projects €3–4 million a year for Rainproof stormwater measures. Rainproof, renamed Amsterdam Weerproof in 2024, now also covers heat and drought.
04
Investment & Resilience
Near-term investment is concentrated on drinking water capacity. Alongside the higher dune ceiling, Waternet is procuring a new slow sand filter at Weesperkarspel, with a tender estimate of €54 million excluding VAT. The city’s sewer programme projects annual investment of €55.9–77.2 million over 2022–2027, at 2021 prices. The water authority is reinforcing regional dikes so that all meet safety standards by 2030.
Climate adaptation is costed but not yet committed. A September 2025 study for the city estimated €1.04 billion of investment needed by 2050, against €1.18–3.46 billion of expected extreme-weather damage over 2018–2050 without further measures. Whether to proceed is a decision for the next city administration.
05
Key Challenges
- Expanding production capacity before demand outgrows the current 95 million m³ a year after 2030.
- Moderating demand, at 141 litres per person a day in 2021 against a national target of 100 litres by 2035.
- Establishing two separate water organisations after the 2026 split, while some services remain temporarily shared.
- Turning a costed climate-adaptation programme into funded, scheduled measures.
- Removing medicine residues and micropollutants at all water authority treatment plants by 2035.
