WATERVILLE — The Kennebec Water District has spent the past several months inspecting 196 locations with fire service connections after it was discovered that firefighting foam got into the water system during a fatal apartment building fire in May, prompting a do-not-drink order for people in the region.

The water district issued a report Thursday summarizing the findings of the audit, which identified only two other locations with vulnerabilities similar to the one at Elm Towers at 60 Elm St. The report lists corrective action taken and fixes in progress.

Elm Towers had no backflow prevention device and the two other locations had defective backflow devices, which are meant to ensure the distribution system is properly protected by not allowing nondrinkable water to mix with the public water supply.

In the case of the fire at Elm Towers, firefighting foam contains contaminants that should not be ingested, so a properly working backflow device would have prevented the foam from entering the public water system.

The report also found there were 68 other locations with backflow devices that only partially protected the water system. These locations had devices in basements that inspectors were unable to test.

“Without testable backflow prevention devices, there is no way to verify the device is working properly,” according to the report. “Starting in October 2023, KWD will notify customers with partially protected services of the requirement for installation of a testable backflow prevention device.”

The report included a letter from Benny LaPlante, the district’s service manager, in which he explained the intention of the audit was to ensure the safety and resiliency of the water system.

“While 68 fire services need modification to meet KWD’s current standards, we have been able to definitely determine KWD does not have a systemic unprotected cross-connection issue,” LaPlante wrote.

The district serves nearly 9,000 customers in Benton, Fairfield, Vassalboro, Waterville and Winslow, drawing water from China Lake. It also provides water to Maine Water, the utility serving Oakland.

Firefighters were called May 22 to Elm Towers, the seven-story independent senior living complex, for a fire on the fourth floor. The Waterville Housing Authority building did not have a sprinkler system because the safety measure was not required when the building was built in 1971.

Tenant Ronald Kennerson, 65, died in the fire.

Roger Crouse, the water district’s general manager, said Friday that after the fire, district officials did not know how many other sites had similar backflow vulnerabilities, so KWD launched the review.

Elm Towers now has a testable backflow prevention device. The two other sites that had no backflow prevention in place included an unoccupied building now disconnected from the system because the building is to be demolished, and another location that is in the process of having a testable backflow prevention device installed, according to Crouse.

The 68 sites identified as partially protected have only single check valves, whereas fully protected systems have a two-check valve device that can be tested to ensure it is working properly, he said.

“We sent letters to all and gave them nine months to modify their plumbing,” Crouse said.

Sites that require fire service must have backflow devices for both fire service and the domestic water system, with the latter used for tap water, flushing toilets and the like. The sites include apartment buildings, garages, commercial shops, municipal buildings, colleges and multistory buildings, according to Crouse.

Elm Towers had a testable backflow device on the domestic side, but none for fire service, he said. Building owners or tenants are responsible for testing once a year and submitting reports to the district.

Crouse said the public can feel confident that backflow issues in the system have been fully investigated, with weaknesses identified and corrective action taken or in progress.

“We feel very confident that the vulnerability that was identified because of the fire at Elm Towers is not systemic,” Crouse said, “and the only remaining one connection is being addressed right now and will be completely protected shortly.”