When I said you could filter the dehumidifier water, I was saying you can probably get the plants to grow. I do not recommend it, even filtered, though. Tap water here in West Michigan (Grand Rapids area city water) is adequate for all AeroGrow gardens. I don't even like using bottled distilled water due to the loss of minerals. Reverse osmosis removes all minerals from distilled water. Most bottled spring water is OK, though.