The city is testing the water at 93-10 Queens Blvd. after two residents got sick with Legionnaires' disease over a 12-month period, officials said. View Full Caption DNAinfo/Ewa Kern-Jedrychowska

QUEENS — The city is testing the water at a Rego Park building after two residents, including one that remains hospitalized, got sick with Legionnaires' disease within the past 12 months, officials said Tuesday.

The Health Department posted notices in English, Russian and Spanish in the lobby of Hampton House at 93-10 Queens Blvd., informing residents that it’s “working with building management to test the water in your building because two tenants have been reported sick with Legionnaires’ disease within the past 12 months.”

The management also posted a flier in the lobby saying that it was first informed about the investigation on Aug. 17 and that in response, “the landlord immediately retained a top environmental consultant,” in addition to a consultant already hired by the Health Department.

"While the risk of infection to tenants is very low, as part of the routine protocol to assess potential sources of Legionnaires’ disease, the Health Department is working with the building management to test the building’s water supply," the agency said in a statement Tuesday.

It was not clear when the residents contracted the illness, but the agency said that they were diagnosed six months apart and that one still remains in the hospital, while the other has been discharged.

The city is obliged to notify tenants when there are two or more cases reported at a single address in a one-year period, the Health Department said.

"DOH is in the preliminary phase of the investigation," the management wrote in its flier dated Aug. 22. "So as of this date, there is no evidence that there even is Legionella in the building's water system, but we want to err on the side of caution."

Photo: DNAinfo/Ewa Kern-Jedrychowska

Last Wednesday, Health Department employees went door to door to notify tenants about the investigation and last Thursday they held a meeting to brief them as well, the agency said.

Several tenants said Monday evening that they saw the notices in the lobby but didn’t know much about the investigation.

The notices advise the tenants that they can still use and drink water, but those who are 50 or older and those whose immune system is weakened, should take extra steps as a precaution, including taking baths instead of showers to avoid water vapor.

Legionnaires' disease is a type of pneumonia, caused by Legionella bacteria, which is typically found in water systems. It causes flu-like symptoms, such as fever, cough and difficulty breathing, but, according to city officials, is not contagious. People can only get sick by breathing in water vapor containing the bacteria.

Each year, the city receives an average of 200 to 400 reports of the disease, which is easily treatable with antibiotics, the agency said.

Earlier this month, the city investigated the water distribution system at a Flushing NYCHA complex after two residents got sick with Legionnaires' disease.

In June, a Legionnaires' disease outbreak killed one person and infected six others in the Lenox Hill area around Third Avenue and East 70th Street, and at least two police officers from the 23rd Precinct in Harlem were also diagnosed with Legionnaires' disease, according to the Health Department.

The largest outbreak took place in 2015 in the South Bronx, killing 12 people and sickening more than 120. It was later traced to 15 cooling towers.

The agency noted that the Rego Park building has no cooling tower.

The management of the building did not immediately return a phone call seeking comment.