I am wanting to collect rain water runoff from my roof.
At this time I have a norman composition shingle roof. Would water collected be free polutants from the shingles. I garden strictly organiclly.

I will be re-roofing one of my out buildings next spring and would be willing to choose another product if the runoff would be cleaner. (Not cedar shingles, cant afford the cost.)

Does anyone out there already catch runoff from their roof? Would be interested in there ideas of how they do it. My garden is about 100 feet from my possible collection site.

Sorry, this posting is a repeat, I overlooked your replies to my first posting, thanks for your input.
However, if anyone has any specific info on the possible bad effects of asphalt roofing, I'd be interested.

I am reluctant to use my roofs as a collection device at this time. But would love to if I knew it was safe.

Boy, I had no idea where this subject would lead when I first posted it!

I collected runoff for several years and never noticed bad effects except the tiny asphalt sediment which sank to the bottom of the barrel. Wish we could stay truly pure, but I'm told that collecting rainwater in a plastic container on a hot day is contaminant enough to influence Bonsai, between the delicacy of the plant, acid rain and plastic contamination. Do the best you can and pray a lot.

We have been collecting rainwater off the backside of our house for years, using buckets. We then transfer the water to sprinkling cans to water the flowers in the backyard. Don't seem to have a problem with it, except that during a dry spell we have to use the garden hose.

debusch of Busch Garden, Jones, MI

When you don't have enough good rainwater, you can do like me a make some good "artificial rainwater".

I fill my 50 gallon rain barrels with faucet water (Note: Most chlorine will evaporate from water in 24 hours anyway). Then I add some human urine or a handful compost into the barrels for extra N and extra microbes.

I use this diluted tea in my aerobic compost piles, my compost tea recipes, and my homemade pesticides.

I have a rain barrel I made using instructions like the ones I have pasted below. I use the water for my outdoor plants, cleaning soil from my hands and outdoor tools. I don't know about pollutants, but it has the advantage of no chlorine.

The 100 feet distance might be solved by combining the collection system with a drip irrigation system. I have heard that the rain barrel will work with such a system, but have not tried (yet) it myself.


Making a Rain Barrel
Rain barrels are a great way to reduce stormwater runoff and to save water for a dry spell. If you have gutters on your house, you may be able to collect 55 gallons of water during a 1/2-inch rain by connecting a downspout to a rain barrel or cistern.
.

Tools:
Electric Drill
15/16" Drill Bit
Sabre Saw
(you can use a hand drill & hand saw)
. Supplies:
Plastic Drum (55 gal. best)
3/4" Spigot (with male threads)
PVC Cement
Caulk
Directions: Use only barrels that have carried food products.
.
Drill 15/16" hole at the first even part of barrel, about 6" to 8" from bottom

Screw 3/4" spigot into hole (should have a snug fit).

When spigot is about 3/4" of the way in, apply PVC cement to threads and finish tightening.

If using a downspout, use a sabre saw to cut a hole in lid to fit spout. After inserting down spout, caulk around the hole.
Other option: Take off the lid of a drum or trash can and cover the opening with a fine fiberglass screen. Place the container where water flows off your roof.

Elevate barrel on 2 to 3 cement blocks to allow easy access to the spigot. (Note: If you want more pressure, raise the barrel higher above the ground.)

You may want to add a second spigot at the top of the barrel so you can direct the overflow through a hose into a specific part of your yard.


from

http://miami-dade.ifas.ufl.edu/programs/fyn/publication...tormwater-runoff.htm

Consider using the new painted steel roofing.It is non toxic and the cost is similer.
As a bonus I have seen it used on some homes and although it may not sound like it,it is very attractive.