LISBON — Water commissioners explained in greater detail Tuesday evening their process of dealing with an arsenic-rich sludge that made its way into the Lisbon Water Department’s filtration plant last week.

When a customer complained of dirty water around 5 a.m. Sept. 4, the department’s lone water operator isolated the issue, discovered elevated levels of arsenic and flushed the water system until 2 a.m. the next morning. A do-not-drink order was issued to residents shortly after the Sept. 4 discovery.

During the order, the town and its emergency response team set up a water distribution system for residents without access.

After the flushing, water sample results from about a dozen tests across the entire water system, carried out by the Lisbon Water Department and Maine Department of Health and Human Services, found no elevated amounts of arsenic. The do-not-drink order was rescinded the next day.

Tina Albert-Dumond of Highland Avenue said since moving to Lisbon in 2020, she has had to replace several fixtures and has a red-streaked bathtub from corrosive water. The experience forced her to come out to her first-ever town meeting to air her concerns about water service and the department’s struggles to communicate with the public.

“I had a leaky pipe in my cellar, and it became a science experiment,” Albert-Dumond said. “There was a stalagmite growing on it and it looked like you were in cave.”

Albert-Dumond also asked commissioners why an alert wasn’t sent in December 2023 when that year’s consumer report noted 15 parts per billion of arsenic in the drinking water. The Centers for Disease Control and Prevention recommend no more than 10 parts per billion for safe drinking water.

Shellie Reynolds, water district interim general manager, said the 2023 consumer report did not include that the reading was taken from a single water source which was “closed, scrubbed, cleaned and sampled” before being reconnected to the entire water system. At no point were those arsenic levels making it into the main filtration system, Reynolds said.

Ongoing complaints about corrosion are being addressed with a control plan initiated in the fall, Reynolds said. Part of that plan includes clearing debris from pipes, including customers’ service lines and boilers.

“It will get better once this corrosion control is in place for a while,” Reynolds said.

As for communication with the public, Reynolds admitted the methods — alerts via social media, notification of local media and use of the town’s emergency response system — were not enough to alert everyone. However, those methods were recommended by the Maine Drinking Water Program. Reynolds said resources from the Federal Emergency Management Agency and the Maine Emergency Management Agency were not cleared until later.

“There is no one method that reaches absolutely everyone, and that’s what we’ve discovered in this process,” Reynolds said, adding that the department will investigate other options like robocalls and text messages in the future.

Reynolds said while the department addresses concerns and complaints as quickly as possible, one of the main issues for the department is understaffing. The department has one water operator making sure the entire system is running smoothly at all times. The department typically has three to four operators. Additionally, Reynolds said she is serving as an interim general manager as the department makes its national search for a new general manager its highest priority.