From comments by President Trump I am forced to conclude that this was probably the MRGC (Minnesota Revolutionary Guard Corps)
NEW: Cyberattacks on U.S. water supply now being reported in 12+ states and 100+ municipalities, though some may be unrelated to wave of suspected Iranian attempts. The nationwide threat follows years of ignored warnings and neglect to water systems. www.nytimes.com/2026/08/05/u...