Foreign actors broke into the industrial control systems of two small private water utilities in Colorado last month, altered pumping cycles, changed equipment settings, and shut off the alarms that would have told operators something was wrong. The state confirmed the incidents on Friday. It has not named the utilities or the attackers.
Both systems are privately owned and serve fewer than 200 people each. The intrusions happened in late August. According to the governor's office, the attackers disabled remote access, switched off alarms, and changed how water was being pumped before operators caught on and regained control. Water quality and treatment were not affected at either location.
"These were brief incidents and the risks were quickly addressed by the providers themselves, who subsequently alerted the state," said Ally Sullivan, a spokeswoman for Governor Jared Polis. "To our knowledge, treatment processes and water quality were not impacted at either provider."
Colorado officials did not name a suspect. Sullivan said the office "cannot confirm what foreign actors may have been involved," but pointed to a CISA-tracked Iranian-backed group that has been working to access drinking water and wastewater systems across the country. Federal authorities have made no formal attribution in the Colorado case.
Part of Something Bigger
Colorado is the latest state in a list that has now reached at least 12 reporting intrusions into water system controls this year. The EPA says more than 100 drinking water and wastewater systems have been hit in 2026, most accessed through programmable logic controllers, or PLCs, connected to the open internet via cellular modems, often without the utilities realizing it.
The summer's single worst episode came on July 26 and 27, when attackers hit more than 30 communities in Minnesota in what state IT officials called a coordinated assault. At least four cities publicly confirmed disruptions. One plant went offline entirely; others dropped to manual operation. In Georgia, hackers took down a pump station, cutting pressure enough that residents were advised to boil water before using it. No one reported getting sick.
The FBI and EPA issued a joint warning on July 30 describing attackers who remotely changed IP addresses and passwords on exposed controllers, locking operators out. In some cases, the intrusions created conditions where untreated groundwater could have entered distribution pipes.
CISA said it tracked attacks against more than 100 internet-exposed water sector systems in July alone, the majority accessed through PLCs attached directly to cellular modems.
The Group Investigators Are Watching
The most scrutinized suspect is CyberAv3ngers, a threat group formally tied to Iran's Islamic Revolutionary Guard Corps Cyber-Electronic Command. The U.S. Treasury sanctioned six of its senior officials in February 2024. The State Department has offered $10 million for information on the group's activities.
The group has run through four documented phases since 2020. It started by exploiting default passwords on Israeli-made water utility controllers, moved on to deploying custom malware called IOCONTROL against industrial and IoT devices, and this year shifted to actively exploiting an authentication bypass flaw in Rockwell Automation's widely used Logix PLCs. No vendor patch exists for that vulnerability.
Six federal agencies, CISA, the FBI, NSA, EPA, the Department of Energy, and U.S. Cyber Command, warned jointly on April 7 that Iranian-affiliated actors were actively hitting internet-facing PLCs across water, energy, government, and manufacturing sites.
Congress and Industry Push Back
Senators Adam Schiff and Amy Klobuchar introduced the Water Cyber Shield Act in August, which would give the EPA authority to audit utilities and mandate corrective action. The bill authorizes $300 million annually through existing water infrastructure funds.
At DEF CON, the National Rural Water Association launched the Water Watch Center, pairing five managed security firms with small utilities at no cost. The program targets systems serving under 10,000 people, which make up 91 percent of the country's roughly 50,000 community water systems.
Denver Water, which supplies about 1.5 million people across the metro area, told Axios it evaluated the threat after the Colorado disclosure and found its systems unaffected. Federal investigators are working with state officials to determine how the two utilities were accessed.
