|Hello! We have an asphalt roof, and are considering purchasing a rain barell to water our vegetable garden. Is it safe to use this water on our vegetables? I have heard mixed opinions. Please let me know.
|The consensus is that there is not a clear consensus. There are significant and reasonable concerns about using rooftop harvested rainwater for drinking or watering food plants. I even consulted one of the more authoritative sources: The Texas Rainwater Manual. The manual was somewhat ambiguous about collecting water from ?composite or asphalt shingles?. Their instructions were: ?Due to leaching of toxins, composite shingles are not appropriate for potable systems, but can be used to collect water for irrigation.? Hmmm? Does this mean the irrigation of plants used as food? Does this mean that asphalt and composite shingles are the same thing or two different things? So I did further research and found information on rainwater collection authored by one of the main manufacturers of asphalt shingles: The GAF Corporation. Their take on collecting water for irrigating vegetables, etc. ? ?Water run-off from asphalt shingles is not approved for potable water reclamation?(including) watering of fruits and vegetables for human consumption.?
There you have it. The lawyers have spoken. I'd use the collected water on ornamentals but not on the vegetable bed. Thanks for asking - I learned a lot during the research process!
You can't drink the water collected, nor should you use it to water vegetable gardens. It's likely to be contaminated with chemicals and bacteria. But you can use it to water flower gardens and lawns or to wash lawn furniture, cars, etc