The five cases of Legionnaires' disease at a Reynoldsburg senior-living apartment complex were diagnosed over the course of a year, which is why the health department waited to issue water restrictions until the first weekend in May.

"We get individual cases of Legionnaires' reported quite frequently," Franklin County Public Health spokeswoman Mitzi Kline said. "Typically, it doesn't require a large case investigation or water restrictions unless we uncover a common link."

She said the first case at the Seton Square East apartment complex, 1235 Briarcliff Road, was reported in April 2016.

"The next case was in November of that year, then December, and then January this year," Kline said. "It wasn't until we saw the case in January that our staff said the address was familiar, so they went back and looked at the cases and saw they were from the same apartment complex."

The apartment complex was notified and began an environmental assessment, then hired a water contractor in February.

Kline said BRC Properties, which runs the complex for low-income seniors, added backflow preventers and other improvements to the water system, then sampled the water in several areas.

"Tests came back positive last week in the potable water system and the same day, another case of Legionnaires' was reported among the residents," Kline said May 9.

She said BRC has been "very responsive and has done everything we asked."

BRC property manager Russ Mathias told residents in a May 5 letter, "We are working closely with Franklin County Public Health and Solid Blend Water Management Solutions to remediate Legionella from our water supply."

The residents met with Mathias and officials from Franklin County Public Health on May 8 to discuss the water restrictions.

Measures to eradicate the bacteria included hyper-chlorination of the water system by a specialized contractor and changes to faucets and showerheads.

Letters were sent to residents May 5 restricting the use of water. In addition to not being able to use the showers, residents are drinking bottled water and limiting all water use. Residents can flush toilets and wash their hands at faucets, but have been cautioned to "try not to splash" the water.

"Legionnaires' is a respiratory illness, which is transmitted when you breathe in small droplets of water that have the bacteria," Kline said. "Showering is one way to get it into your lungs and it can more easily affect the older population or someone with respiratory issues."

She said the outbreak of the disease at Seton Square was minimal compared to what struck a Reynoldsburg retirement community in 2013. Six residents died during that outbreak at the Wesley Ridge Retirement Community in July 2013 and the disease affected 36 people.

"That one may have been caused by the cooling tower, where chlorine levels were not staying high enough to kill the bacteria," Kline said. "Cooling towers tend to spew out vapors."

The five people affected by the disease at Seton Square were two men and three women ranging in age from 55 to 83.

Kline said Legionella bacteria was confined to the Seton Square water system and is not in the city's water supply.

"The city of Reynoldsburg gets water from the city of Columbus and they are required to continually test chlorine levels," she said. "Something is allowing the chlorine levels to break down within the Seton Square water system."

She said water restrictions would continue at the apartment complex until testing produces several negative results.