Can I Recycle the Water from my HVAC System?

When we moved into our house several years ago, we noticed that a pipe carried water from our AC and Furnace unit to the utility sink. The water that came out of this pipe was clear, and seemed clean enough. I wondered: could I somehow recycle that water to use in my garden? One reads of grey water systems. Could this pipe, which seemed to be carrying condensation away from the heating and cooling unit, somehow be put to work for the sake of my parched plants in a sort of homemade grey water system?

I never knew who to ask about this. The heating and cooling guys didn’t seem to know if it was safe, and there was nothing in garden publications or on popular websites that ever even mentioned it. I wasn’t even sure what to call that pipe. I also wondered if I was the only person in the world that had such a thing. I mean, unless you work with HVAC systems, how often do you look at someone else’s furnace in the up close and personal?

But last Friday, while attending the Green Matters Symposium at Brookside Gardens, I finally got my answer. Yes, said Paul Bassett of Water Management Incorporated, you can use it.

Paul was not just speaking to me. In fact, he was addressing the whole room and urging people to reuse this water if possible. Many of the pipes which carry this “condensate” away from HVACs go directly outside, he said, where they drain somewhere in the yard. Others, like mine, empty to a basement floor drain or utility sink. Either way, the water can be re-used in the garden.

There’s an important catch, however. Due to concerns about bacterial growth, you can’t reuse it for overhead irrigation, since spraying could encourage the transmission of Legionnaire’s disease. I assume that it would also be a very bad idea to use that water on houseplants or anything else inside. But by placing a bucket under the pipe (like those five gallon ones they sell at the hardware store), you can catch the water and then pour it at the base of shrubs or trees in your yard.

Very cool. I can’t wait to try this out. Thanks, Paul!