Rain Barrel Tips: Using Rainwater from the Roof

Jamie asks another great reader question. She asks us the following:

“Is it OK to use rain water collected from a roof with asphalt shingle roofing on it to use in a vegetable garden?”

This is another great question. While you may be worried about using rainwater from an asphalt shingle roof on a vegetable garden – don’t be. Your vegetables will be just fine. When you think about it, before you had a rain barrel, you most likely had rain water from a downspout pouring out onto that spot in your lawn, and everything’s been alright. In this case, you are talking about vegetables, and we understand you’re going to eat the vegetables. However, there’s no worry. You’re going to take the water and pour it in the dirt, and it will get filtered by the dirt, and then the root of the plants…so it’s no problem at all.

So in summary, it’s perfectly fine to use rainwater in your vegetable garden! Have at it.

Thanks for your wonderful question, and best of luck with your garden! Hope it turns out quite well!

  1. I would like some statistical numbers of how much rain water comes off the roof.I have heard,but have forgotten the numbers. Thanks

    • Eleanor,

      You can collect hundreds or even thousands of gallons of water from your roof top. It all depends on the amount of rain the size of roof and your ability to store the water.

      Here is a quick formula to figure out how much rain you might collect on your roof.

      1 inch of rain on a 1000 sq ft roof yields 625 gallons of water. To calculate the yield of your roof, multiply the square footage of your roof by 625 and divide by 1000.

      I hope that helps!

  2. we’re interested in collecting rain water from our upstate NY asphalt roof for drinking/cooking purposes. My husband has been filtering it for a few years now and we’re expanding our operation to include collection of about 1,000 gallons of water annually. Any issues we should concern ourselves with. We’re using a Berkey water filter. We’re also storing water for about 6-9 months. Anything else we should know. I’m not clear on bug protection and water safety in particular. Any help would be appreciated. TY

    • @jary, As far as I know these types of water filters are designed to be used for tap water and not water that comes off your roof and collected in your rain barrel. Typically rain water collection, especially water from your roof top, is used for watering lawns, plants and gardens. However if you have been doing this “for a few years now” and not experienced any problems then you may be ok. However I strongly suggest you contact the filter manufacturer and get their opinion on using it on water collected from your roof top.