Legionella was a problem to the Legionnaires because the HVAC system was spraying bacteria laden droplets upon them for days on end; the ones that got bad sick from it were the ones with compromised immune systems. Transmission is by aerosol distribution and inhalation. Run the outflow directly into the earth via seep hoses, and there will be no aerosol problem. The other bugs are scary, but, again, if you put the condensate directly into the soil, all those scary pathogens will merely be joining others like them-clostridia varieties come to mind-tetanus and gas gangrene bugs-that are already living happily, and safely, pretty much-in the soil. All of the bacteria that cause infection in humans are around us in the environment all the time, colonizing our skin, saliva, telephones, computer keyboards-and our immune system fights them off handily. Infection occurs when there is a breakdown in the immune system-a break in the skin, nutritional deficiency, other disease. Anyway, the condensate is probably no more dangerous than any other water in the garden.