I wouldn't feel safe using such water. Dehumidifiers remove moisture- and possibly pathogens/bacteria/mildew- from the air. At least some of that Is going to end up in the water. Whether the levels would be hazardous Im not sure, but my instinct says it well could be. I don't even use the water drippings from my ac because insects crawl into them and die, which again adds unwanted nutrients to the water.