NEW YORK (CBSNewYork) — Another cluster of Legionnaires’ Disease has been identified in the South Bronx, and city officials have already taken steps to stop the spread of the disease.

Over the last six months, four residents of the Melrose Houses in the South Bronx have come down with Legionnaires’ Disease. The most recent patient was diagnosed last week. Another case was diagnosed earlier in the year, and two others were diagnosed during the South Bronx Legionnaires’ epidemic earlier in the summer.

Mayor Bill de Blasio said tests were then conducted on the water systems in that public housing complex.

“In one building, we found a positive result. Now, it was a very faint positive result. But out of an abundance of caution, we decided that in that one building, we would take additional steps,” said the mayor.

Steps that included shutting down the hot water and installing filters on all faucets, 1010 WINS’ Al Jones reported.

The city late Thursday said the hot water was restored around 8:30 p.m. to a building at 681 Courtlandt Ave. where the positive result was detected. Residents have been advised that they can use hot and cold water normally.

The mayor stressed that the result was only a faint positive and that more tests are being conducted.

Now, this case differs from earlier cases in that instead of the source originating from cooling towers, the bacteria was detected in the drinking water system, Jones reported. Though only in the hot water.

The city’s health commissioner continued to stress that the drinking water is safe.