I’m looking for information regarding the use of rainwater collected from an asphalt shingle roof to be used in watering a food garden. I’ve searched the old posts and I’ve read in several places that it is not a good idea to use water from an asphalt roof for a food garden, but I’ve never been able to find any specific references to any published studies regarding this. Does anyone have any references to studies on the toxicity of rainwater from asphalt shingle roofs or specific data on the use of this rainwater for a food garden?

Asphalt shingles collect too many coliforms… and also leach out all kinds of oils, and petroleum products that are very hard to remove with filters… stay with enamled metal roofs,or plastic sheeting, or plastic covered tarps, or glazed tile roofs.

So for those of us with shingled roofs, you’re saying that covering those roofs with plastic sheeting would make the runoff acceptable? I’m wondering what kind of damage that would cause to the underlying shingles/roofing. I’m thinking trapped moisture from pinpricks, condensation, etc. I’m trying to determine whether it is feasible to collect rainwater for household/garden use without replacing my roof.

You run no more risk collecting rainwater from an asphalt shingle roof than any other roof. I presently have a slate roof, that was never taken good care of, before I bought this property, and it will be replaced soon. Selling the slate will more than pay for my new roof. I have town water and a well casing that I maintain, in case of ‘whatever’. I have always done a rudimentary filtering of my rainwater with sand and charcoal, no matter what I use it for. I treat the filter occasionally with bleach water. I also do regular testing and checking of my water with my microscope, and keep photo files of my water.

My town water has scared my more than the rainwater, with the red growth that collects in a standing container. I filter the water for drinking and bathing, also keeping the ‘hard’ sediment from collecting as bad in the hot water tank. I clean out my lime, etc., out of the hot water heater every other year, at least, with a Calgon solution (which it was originally invented for, industrial boilers) then after several rinses I can hope for my heating elements to last another couple of years. The only adverse reaction I had to the rainwater collected this way, might be the way my ears are starting to get pointed…you know, like Mr. Spock!

Forgot to add that I can’t use my cistern, since former occupants, whom worked for a garbage company, filled it with wood ashes (all the way to the top). They also had built walls, on the north side of and in the south side, of the garage, where they piled mounds of trash??? This all had to be cleaned out so I could find the two bumble bee nest (never saw one before)…with about 500 in the back of the garage, and 150 in the front. Not to mention the thousands of wasps in a bean bag chair size nest in the rafters of same garage. And this years the dozens of yellow jackets nest I had to remove!