Does the condensate drain on a conventional domestic air conditioner provide a risk of catching the Legionella disease. It has been suggested by my local authority that the reason for connecting the condensate drain to sewer is to reduce the risk of contracting Legionella.
We are not aware of any cases of Legionnaires’ disease acquired from a condensate pan or drain. There would be little opportunity for significant exposure. One benefit of connecting the drain to the sewer is that there might be no need to chemically treat the condensate pan. These pans can often be the source of foul smelling bacteria and molds.