But my husband fears that the runoff from our composite shingle roof would be too dangerous to put on edibles, so he's saying NO outright for the veggies.

Do any of you use rainwater systems from your roof? Do you need to filter it?

In our landscape, aside from my veggies and container citrus trees, the only other thing that needs regular water is our lawn. everything else is a drought resistant native. I posted a question about rainbarrels over on another board and I got the sense that doing a barrel for my lawn may not store enough to make it worthwhile, and there were the inevitable comments from folks who thought my lawn unworthy of rainwater; that I should just let it die in the face of a possible drought. (I'm in the SF Bay Area, and though we're not rationing yet if we have another low rain year we will be.)

Bottom line is, I'm thinking of creative ways to use less municipal water and be more environmentally sound.

Ideally, I'd like to find a way to harvest rainwater for my veg garden if I could mitigate the fears of roof chemicals leaching into it. If that won't work, I would like to figure out a way to make it work for my lawn, if only to save it for watering in the hottest summer months when our municipal water is likely to ration it out.

Any thoughts?

len

I have included a good link to a very good discussion on this topic. To sum up:

"The consensus from web sites and these interactions seems to be that unless the roof is designed with materials and methods intended for rainwater collection, there is a possibility that toxic substances will end up in the water. The point made about the rainwater being toxic enough to kill moss and mildew suggests that it may actually be toxic to garden vegetables if collected water is a primary source of water for a garden."

Hope this helps.
Michael

So that shoots a hole in my tank, literally. Unless I convince him to get one for watering the lawn. Hey, at least it's conserving some water even if it's not the most worthy of causes in some people's eyes.

Thanks for the link.
-kristi

Marcia

What are they Michael?

Wayne

Lets make this really, really, really simple so even the perennial fearmongers can understand it.

Go outside and look at the areas your roof water runs off too. Are there plants growing there or does the area look like somebody sprayed RoundUp there?

If the former then it is as safe as you are going to get in this lifetime and if the later then don't use it.

What *exactly* is in any roofing material that would be harmful in the catchment water?

Good grief, some folks will worry about anything. Just silly.

If you're going to worry about the chemicals being leached out of the shingles, then you have to worry about the chemicals that are in the rain water in the first place... before it even touches the shingles. Not to mention, assuming that you're using city water on your garden, what about the chemicals in that?

I would worry if the water sat up on my roof for a decent period of time before being flushed into the gutter system... but that doesn't happen. By the way, the water in the rain barrel does have all kinds of stuff in it that a bucket of pure rain water wouldn't have... but it's stuff that washed off the roof, like Maple helicopters, moss, bugs, etc... I have yet to see ANY roofing material.

I have seen bits of roofing get flushed down the gutters when I lived in a house with an old roof. Supposedly the best roof for collecting water is a metal one.

Crankyoldman: Nothing says refreshing like a tall glass O' bird poo water.

For bacteria/viruses could you just use a water purifier like the MSR Miox that you would use when backpacking to "zap" the water killing all organisms? This would at least eliminate the bird poop threat if not the chemical threat.

Greg
Nevada

obviously, it is a personal decision if you want to use the rain barrels for your garden. one thing that has not been addressed here is what exactly those potentially toxic chemicals might be. without knowing that, i certainly wouldn't call it "silly" if someone decides not to use the rain barrels for their veggies.

http://www.nrdc.org/water/drinking/uscities.asp

There is a big benefit from rainwater, especially after a thunder storm, that no one has picked up on. Nitrogen! The electricity from lightning charges the atmosphere and converts a mesurable amount of nitrogen into the rainwater. Take notice the next time you have a thunder storm, of the great sudden growth in your plants. It's free fertilizer!!

Ron
The Garden Guy
http://www.TheGardenGuy.org

An occasional bird-poo diluted in 10,000 gallons? Give me a break! Modern society's many physical ills are caused IMHO by sanitising, purifying, deodorising, anti-bioticising(?) everything we and our children touch.

Since I've used rainwater exclusively, I've grown to 7 feet tall, 240lb of rippling muscle, my IQ has increased to 200 and beautiful women beat a path to my door!

Ever had a hot, soft rainwater shower by candlelight (I also have an unreliable solar electricity system!) that feels like being washed by a gentle waterfall?
I do, every night. On the rare occasion that I have to shower with town water, I get out feeling like I need a shower!

It's that "town" water that scares the heck out of me!

Regards,
Shax (in Oz)
(Hiya, alfie!)

"shax said,
Since I've used rainwater exclusively, I've grown to 7 feet tall, 240lb of rippling muscle, my IQ has increased to 200 and beautiful women beat a path to my door!"

must be the possum poop that does it hey?? lol lol!! i only gets a bit of bird poop in mine huh chcukle?

but yes we use only tank water, though in the 'burb's we have turned of our town water, only ever feel clean after tank water shower. we have a tiled roof (not by choice or it would be corrugated)

len

If you're going to water your vegetables with toxic water, come on guys, even the people who manufacture these shingles say they are unsafe for watering vegetable gardens. There's so much denial in manufacturing that I really sit up and take notice if the people who make the stuff say it's bad for you.

Michael

we have a 25k/litre tank around 5k/imp/gal, for us that would be enough for all our water use through the year with our average rainfall in around the 1k/mm range. but that is because we recycle all our used water, some into the garden (only got 16sq/mts), other into potted plants and some goes to flushing solids only in the toilet, urine never gets flushed mine gets bucketed for adding to the kitchen pre-rinse water and wash water for the vege' garden.

target to use all water more than once.

no science needed in rainwater collection just some common sense(type of roofing! we over here only get coloured cement tile and corrugated colour bonded zincaluum) and the need to see that if you are in low rainfall areas there are not a lot of other options, all the rest is fear hype.

len

I work at the state water safety department. Water for crop irrigation is not held to the same standards as drinking water. For example, farmers can water crops with water pumped straight from a river, no chlorination needed, while water for human consuption MUST be filtered and chlorinated.

I live in an arid area in the midst of a drought that's lasted two years so far. It seems a damn shame to waste drinkable water on plants when they can do just fine on harvested rainwater and even recycled greywater (water that has be used for things like dishwashing, laundry, or showers, as opposed to "blackwater" which is what goes down your toilet).

I think we should be concerned not so much with what's in the water, but what the plants actually absorb and ends up in the vegetables you eat. I really don't think that water for irrigation needs to be pristine like drinking water should be.

Does anybody know if any of these shingle chemicals actually end up inside vegetables when watered with harvested rainwater?

Turns out that they happened to be outside right after the government had set off a nuclear device in Nevada, and the winds had carried the fallout to their high school.

Aside form chemicals that many studies have shown in roofing materials that are khown to be unsafe, there is also bird droppings, etc. Take alook in your gutter some time and see the crap collected in there.
Now one might say that these things may get on/in the garden anyway, butit is different. Do a google search on this and you will see factual info advising against this.
that being said, you could easily build a tin roof if you have room in your yard cheaply to collect the water in a rain barrel, and more then one if you have room and have all the water you want. A lotof times the county extension offices will offer classes on rain barrelss and give a bunch away or sell them cheaply. Of course there may still be the bird dropping issue, but owl it to keep birds off of it at least.

Good luck.

I would think the massive quantities of rain pouring over a roof would make whatever came off the roof fairly faint. Certainly we are not told to not grow vegetables near the house, and rain rolls right off the roof in some areas. I am sticking with my rain barrel system. What comes out of the ground is likely to have herbicides in it, I live in any area that has been heavily farmed for at least 100 years.

Marcia

I want to put barrels under couple roof corners because I don�t like river of water from downspout crossing backyard porch.

Rain barrels aren't going to help with this. They only hold 30-50 gallons of water which fills very quickly with a decent rainfall. You would be better served using those flexible plastic pipes that attach to the downspout and can be directed to wherever you want the water diverted to.

Certainly you could employ rain barrels into this system, but they don't hold enough water to stop a down pour from making rivers over your porch.