Survey reveals dozens of Danish water utilities have faced cyber attacks

In the autumn of 2026, the Danish Water Utilities association conducted a survey of 691 consumer-owned water providers and learned that a number of them have been targeted by cyber attacks. Udsholt Waterworks in Gribskov Municipality, which supplies roughly 5,000 homes, suffered an intrusion in autumn 2025 that required the utility to cut its internet connection and run in isolated mode; the outage was not apparent to customers.

A previous attack in December 2024 affected a plant in Tureby-Alkestrup, where hackers altered water pressure, causing pipe bursts, and a Russian hacker group later claimed responsibility on the social platform X. Following these events, Danish security services elevated the threat level for destructive cyber attacks against the nation’s critical infrastructure, including the water sector. The heightened alert reflects concerns that hostile actors may increase hybrid-war tactics against Western and NATO targets in the coming months.