Mayor Bill de Blasio and the health commissioner were once again in the borough addressing Legionnaires' disease concerns as another cluster of legionella bacteria was discovered Tuesday in the South Bronx. 

Health officials are still testing samples of the water supply collected at the Melrose Houses. The building at 681 Courtlandt Ave. is the only one that tested positive during a preliminary test.

The mayor and the health commissioner say the water supply is safe. They confirmed the hot water has been turned off at the buildings since that is where the bacteria is usually found.

According to the mayor, six more buildings are going to be tested, and they hope to have those results by Friday afternoon.

The mayor says 50 percent of filters were installed in apartments. He adds that the whole complex will be installed with new filters by Friday morning. 

De Blasio says they hope the hot water will be turned back on by Friday afternoon, but only after they receive results of testing done over the last 24 hours.