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

http://www.uri.edu/ce/healthylandscapes/Rain barrel bro.pdf

It says not use that water on vegtables close to harvest time. and that you must wash the produce after harvesting, well. (DUH)

there is concern that roof water would place to much minerals into the garden, like zinc. but these appear to just be fears and not documented proof. For now, my plants will get what I can collect. People complain about bacteria from bird feces on the roof. Well birds crap in my garden and fertilizer is chicken crap.

Water your flowers, bushes, and grass to your hearts content with this water.

By the way, I have not heard any comments on the type of material the barrels should be made of. Are there certain types of plastic barrels that should be avoided, especially in S Texas heat that would practically cook the water and potentially cause a plastic leaching effect? I know that I can taste plastic in a water bottle left in a hot car.

I have a barrel for rainwater made of some kind of poly something or other plastic and at the time I purchased it years ago it was supposed to be the way to go for not leaching. I would like to purchase at least one more but would like to hear the lastest buzz on the best barrel.

Thanks!

Roger

I use a reverse osmosis systen in the house, that reduces the pollution in city water by 98 percent but I still don't trust city water. I want to use the natural water from the sky. So my aim is to get a good portion of my drinking water each year from the roof. I've been looking at water purification systems, for example hooking up a 3 stage filter to the barrel, consisting of sediment, carbon block, and ceramic, the latter to replace the RO membrane as that is not needed outside. The TDS is already good.

Looking at all this I'm thinking it sure would be good to not have to remove all that black shingle crud from the water at the start! So now I'm thinking to have that 1/4 of the roof covered with metal. My understanding is that stainless steel is the best metal but expensive. For those of you who are drinking rainwater from the roof, what would you recommend in my case? I'm estimating there might be 500 square feet of roof. And how to avoid the high cost of roofers? Thanks

I put a large 2" PVC ball valve in place to separate nine barrels from the other three. This will allow me to have the valve open when it is raining to fill all 12 barrels. Then I can shut the valve and drain the three barrels into another set of three just below those. One of them is filled with compost and dead plant material. By the time the water trickles through this, it is then distributed amongst the four barrels. I can then use a pump and pump the compost tea back into the three barrels above, open the ball valve, and then when I water my garden with the PVC irrigation system, it has a 3-part water to 1-part compost tea mixture - instant fertilizer!

Definitely was a lot of work but am happy with it. I had a nine-barrel system up until this fall and then added the other three with the ball valve - so I'll begin using that this year.

Here are some videos I've made. I still will need to make another video when the spring comes around to show how the new compost tea system works.

Rain Barrel Water Collection System
PVC Irrigation System & Rain Barrel Integration

To be clear, this is NOT drinking water and it says it right on the barrel. Any rain water that is collected for drinking would have to be filtered several times I would think.

Unless you are growing in a greenhouse that same water with the same pollutants fell on your garden. The pollutants you mentioned are found in the air around cities not in roof tiles. Whatever chemicals there are contained in your roof tiles make little difference in the grand scheme.

Your tap water has all sorts of nasty chemicals to. Arsenic, chlorine etc...