I'm looking into collecting rainwater off my shingle roof, but I've heard concerns about potential contamination from the asphalt and tar used in roofing materials. Is there a risk that this rainwater could harm my outdoor plants, specifically those I intend to consume? Should I take any precautions, or is it generally safe to use?
3 Answers
It’s a complex topic! The biggest concerns are contaminants like heavy metals that could accumulate in rainwater. If you're harvesting rainwater, conducting a quick pH test might be beneficial, as acidic conditions can hint at potential problems. I've read about lots of different opinions; some people even recommend only utilizing rainwater for ornamental plants and being careful with edibles. DIY filtration systems might also help.
Personally, I'm not too worried about it. Just make sure you avoid using it on crops that will be eaten raw. We've had good luck using rainwater from asphalt roofs, especially if you're just watering the garden soil instead of directly soaking the plants. A mesh filter can help keep out debris and contaminants before the water even reaches your barrel.
Yes, there can be some risks with using rainwater from an asphalt roof, mainly due to the chemicals in the shingles. However, many folks successfully use it without issues. One thing you might consider is a 'first flush' system. This setup diverts the initial runoff— which contains most contaminants—before allowing cleaner water into your barrel. Beyond that, flushing your veggies with fresh water before harvesting can add an extra layer of safety.