Plymouth water facilities targeted in suspected cyberattack; quality unaffected

Plymouth officials said a suspected cyberattack disrupted cellular communications connected to two water towers and multiple lift stations, while reporting that water quality and water levels were unaffected.

The city posted its notice at 5:34 p.m. Monday, July 27, after the outage began overnight Sunday, July 26. The reported disruption involved communications used to monitor the facilities, not a reported loss of water service, contamination or shutdown of the underlying water system.

Crews switched to manual operations

City crews continued operating the affected facilities through manual procedures, according to the City of Plymouth notice. The city said water levels and water quality remained unaffected and told residents they did not need to change their water use.

Residents can therefore continue normal household water use based on the city’s current guidance. They should rely on future official updates for any change involving water safety, service or conservation instructions.

A broader Minnesota water-system concern

Reporting from FOX 9 and MPR News placed Plymouth’s incident within a wider series of cyber incidents affecting water facilities in Minnesota. FOX 9 reported that Plymouth, South St. Paul and Braham were among the communities dealing with incidents on Monday.

The situations were not identical. In Plymouth, officials reported a communications disruption and a shift to manual operations. In Braham, officials said a cyberattack briefly knocked the city’s water plant offline before crews addressed the outage. Officials in the communities told residents they could continue normal water use, according to FOX 9.

What remains unknown

Plymouth described the event as a suspected cyberattack. The public notice did not identify a responsible party, motive or confirmed scope of any broader system compromise. It also did not establish that communications had been fully restored; manual operations were described as the ongoing response.

Minnesota Department of Health guidance says community public water systems that use operational technology, such as SCADA systems, must conduct annual cybersecurity assessments and certify completion with the department. The guidance also outlines incident-response contacts and coordination steps. It provides statewide context for the response, but it does not indicate that Plymouth violated any requirement.

For now, Plymouth residents do not need to alter normal water use based on the city’s notice. The immediate operational issue is the loss of remote communications at several facilities, with crews continuing to manage operations manually while the incident is assessed. Residents should monitor official Plymouth updates for any change in water safety, service or conservation guidance.

Sources

• City of Plymouth notice
• FOX 9: Several MN water facilities targeted by cyber attacks
• MPR News: Officials in Minnesota cities say cyberattacks targeted water systems
• Minnesota Department of Health cybersecurity guidance