Rain barrels to water fruit?

lsohDecember 10, 2013

Is anyone using rain barrels as their water source?

There are 2 reasons I was interested in using rain barrels.
1) My blueberries would probably be happier with rain water than with our city water.
2) At this point, we are free to travel. But my containerized fruits need daily water. Our wonderful neighbors water, but it's a chore. I was hoping to set up 3 strategically located rain barrels with drip lines / soaker hoses. I have no experience with these. I was thinking that the neighbor could simply turn on and off these lines. (From what I see, timers are expensive for my purposes, and some require electric that wouldn't be available.)

While researching how to make a rain barrel, I ran across articles warning against using roof water run off to water edibles. The concern is heavy metals. Apparently there are 2 applicable sources of heavy metal contamination. A) Composition of asphalt shingles. B) Heavy metal dust settling on the roof from air pollution. (Seems to me if that's a problem, it would also be a problem in the rain itself.)

Does anyone have any thoughts on this?

Any other suggestions? Thanks.

Thank you for reporting this comment. Undo
fruitnut Z7 4500ft SW TX

Well water would be easier to mechanize than rainwater because it doesn't run dry and pressure is more constant and higher. Also it takes big barrels and large collection area to water many trees. As a result I use rainwater for blueberries only.

    Bookmark   December 10, 2013 at 4:32PM
Thank you for reporting this comment. Undo
drew51 SE MI Z5b/6a

Well most states have facilities to test water for drinking. You should test your well water before drinking it, so you could send samples in to test. I always wonder too about arsenate and lead in soils. Something to think about too, is most water plants well no all water plants do not remove heavy metals or solvents etc. They just sterilize the water.
Depending on your source of drinking water, it could be worse. We get our water from the Great Lakes, and last I looked it rained a lot in them. They do monitor levels, a certain amount is considered safe. Why many people filter their water. My dad lived to 86 drinking it, so I'm not that concerned.

    Bookmark   December 10, 2013 at 4:33PM
Thank you for reporting this comment. Undo
drew51 SE MI Z5b/6a

Yeah some people install pumps to pressurize rain barrels, it can get expensive, they break down all the time. I would hook drip lines to my house water and only use while away. Mechanical timers are better because with electrical if your power goes out you lose all settings or if your batteries run out or are compromised by water. Mechanical just keep going. I'm not even sure you can buy them anymore? I went the biological method, and make my kids come over and water everything. I finally found a use for them :) They watch the dog too!

    Bookmark   December 10, 2013 at 4:45PM
Thank you for reporting this comment. Undo

How polluted or not your precip is depends upon the details of your air quality, location, and roofing. I know quite a few folks who use roof water off asphalt shingles that are old (10-15+ yrs). Their thinking goes that all the soluble bad stuff has already washed out, but I have not ready any studies to confirm this. (Would be nice hear if this theory has been tested anywhere)

There are still available battery powered hose timer valves. The one I am thinking of has a ball valve (two actually one per zone)), so no pressure loss. Should be fine for a low pressure drip system or the like. Batteries tend to last a full growing season so should handle any vacation time. Also I've seen several places with a purely mechanical hose timer (0-2 hrs), however it needs to be set manually at each use. (But it would reduce the work your tender needs to do, just come over and turn a dial or two).

    Bookmark   December 10, 2013 at 10:49PM
Thank you for reporting this comment. Undo
Bradybb WA-Zone8

I used a rain barrel this past Summer for a small garden,with drip irrigation and a timer.
I built a raised bed where I work and was watering by carrying five gallon buckets,because the source was too far and not accessible with a hose.
A customer came by and gave me a rain barrel with all the fittings.I needed a way to fill it,because it doesn't usually rain in the Seattle area much in the Summer months.So I bought a little cart from Harbor Freight that was rated at a thousand pounds.I left the barrel on it all the time and went back and forth to the water source when empty.It wasn't perfect,but it did beat hauling those buckets.
The timer I think was an inexpensive Rainbird,about twenty dollars from Home Depot.It took two AAA batteries and they lasted all Summer.It did fine with the low pressure coming from the barrel.The problem was,when it did rain enough,the battery compartment took on water.I fixed that by attaching a plastic gallon milk jug,with it's bottom cut out,to cover the whole timer,held in place with a rubber band.for easy removal.The timer is also fairly simple to operate and has multiple settings.Also quick disconnects are the way to go for fittings.
It went through a lot of water.There were about fifty emitters turning on every six hours for about fifteen minutes,so the barrel had to to be filled about every other day.
Also,I don't think a soaker hose will work with a rain barrel,not enough pressure. Brady

This post was edited by Bradybb on Wed, Dec 11, 13 at 5:02

    Bookmark   December 11, 2013 at 4:56AM
Thank you for reporting this comment. Undo
drew51 SE MI Z5b/6a

One thing I noticed was how much water I was using, it's got to save some money using rain.

    Bookmark   December 11, 2013 at 7:15AM
Thank you for reporting this comment. Undo

Rainwater harvesting is practiced extensively in many places, being the sole source of water in places like parts of Australia and remote sea islands.

Here in the Southwest it is really common and encouraged, the water authorities offering incentives for it even. It of course reduces use of city/well water sources and mitigates storm water runoff problems.

I have about 5,000 gallons of rainwater storage capacity in two underground cisterns and one smaller above ground stock tank. I estimate that I get to use about 15,000 gallons of rainwater from these tanks per year, representing about $200 in water bills where I live, not to mention the overall fossil fuel savings compared to all the well drilling, pumping, pressurizing, chlorinating, etc... that my local well water department does to get the drinking water to me. The storage cost me about $800 dollars initially (this is much cheaper than the going rate), so paid for itself long ago). Plants really like rainwater, and I really don't believe there is any concern about quality, unless you have something especially toxic on your roof, which would be a serious environmental concern anyway.

    Bookmark   December 12, 2013 at 9:42AM
Thank you for reporting this comment. Undo

I use 7 large plastic garbage can to catch the rain off my garage edge. Garage has no gutters so rain just falls off the edges.

That way, I get lots more rain water that one rain barrel.

Simple. Effective.

    Bookmark   December 12, 2013 at 6:25PM
Thank you for reporting this comment. Undo

Here is an article from NC State Cooperative Extension looking at the quality of water from various roofing materials. All in all it doesn't look too bad. There is a big chart on the 3rd page.

The main thing to note here is that the many of the bad things found in the water were already present in the rainwater prior to contact with the roof. Aluminum, lead, and zinc are all elevated in roof runoff, however only lead is a health concern. Lead levels in rain water (no roof contact) were 2x the EPA levels for safe to drink. Asphalt shingle, galvanized iron, and wood shingle had the worst lead levels (3-4x the EPA levels for drinking water). To me that doesn't sound all that high. I guess it depends on if the plant type concentrates lead in the edible portion.

One thing that would make some sense, in addition to not using runoff from new roofing material--try not collecting the first few rains of the season or don't connect the barrels until after the first few hours of rain. This could flush off any accumulated pollutants.

Here is a link that might be useful: Report about water quality in roof runoff

    Bookmark   December 12, 2013 at 7:24PM
Thank you for reporting this comment. Undo


    Bookmark   December 15, 2013 at 8:46PM
Thank you for reporting this comment. Undo

Thanks rhino, an interesting study.

I noted that the Texas rain water started with a pH of 5.55, before it hit the roofs. That is acidic enough to grow blueberries. And I suspect it may explain the high levels of metals after this water hit the roofs, as that acidic a water wash is going to pull some metal of any metal it contacts (metal roofs or nails and the like in other roofs).

It would be interesting to see what sort of numbers you get in an area that has fairly neutral or even alkaline rain water. I would expect it to pick up far less metal. Also would be nice to see something on hydrocarbons picked up from asphalt shingles.

    Bookmark   December 18, 2013 at 8:45PM
Thank you for reporting this comment. Undo
skyjs(z8 OR, USA)

THe shingles are made out of tar. I don't want tar water in my food or water. We are considering a metal roof. We will do it in tandem with a solar roof.
John S

    Bookmark   December 18, 2013 at 9:43PM
Thank you for reporting this comment. Undo

So I did a search and found an interesting study on collected rain water quality. Here's the link (hope it works here):


In short, metal roofs seem the best in terms of low contamination, but none are really that bad as far as irrigation water is concerned.

There are some studies which point to asphalt shingles as being good in terms of PAH (organic hydrocarbon) contamination. But there are conflicting conclusions on that.


What I would like to see studied is contamination levels on more modern roofing materials, such as the factory baked on painted metal roofs (standard fair for metal barns and roofs today). And some studies in an area with neutral rain water (the Texas study had fairly acidic rain). I have heard that the factory painted metal roof material was tested as the cleanest of the current roof materials, but I have not seen the tests that bear that out.

In general though, it seems that using collected water to water a garden or orchard is likely safe, as long as you are not in an area of high pollution, and you don't have an unusual roof (like lead coated copper). If you have zinc surfaces that the water travels over (roof, gutters, etc) then high zinc levels might be a concern over the long run. Or if your roof/gutters have solder joints (lead) then that may be a concern. The more acidic your rain water is, the more concern about picking up heavy metals.

Anyway, that's my take. You can find quite a bit of stuff to read on this topic with a quick internet search, so do your own research. Disclaimer, I am not a doctor nor a chemist and do not play either of them on TV.

    Bookmark   December 18, 2013 at 9:44PM
Thank you for reporting this comment. Undo

That is an interesting (if long) paper. I like their little mock roofing setup but it would be nice to see a larger study with actual installed roofs. It does certainly seem that avoiding the first flush of water off of any roof helps cut down on all sorts of contaminants. As you said, I think the soldering/sealing/nails used/etc may have a significant effect on contaminants from any roof.

They rigged up a "first flush" tank (figure 4-2) that would be pretty easy to do one's self in between the roof and the collection tank. All you'd need to do is empty that flush tank when there is a significant break between rainstorms. You could even store that water separately and use for your non-edibles.

    Bookmark   December 19, 2013 at 12:47PM
Thank you for reporting this comment. Undo

I water a lot of my plants and my entire garden with rainwater collected in two huge cisterns, but I only water my blueberries from my well. Why? Because while rain where I live typically has a pH below 4.5, once it sits in the cistern for a few weeks it will climb to over 8 due to algal growth. My well water has a pH of just above 5, perfect for my blueberries. So rainwater can work fine, but keep an eye on it's pH.

    Bookmark   December 26, 2013 at 8:37AM
Thank you for reporting this comment. Undo

I ordered a 55 gallon tera cota rain barrel from Home Depot that should arrive this week. It has a flat back so that I can put it against the wall on my patio (see patio picture). If I like this one I will get two more, one for another downspout on the other side of the house and another to collect the overflow from the one I just bought. Ideally one should be able to attach drip irrigation hoses so that it is more or less self-watering. I don't beieve that a lot of money will be saved since I only pay about $25 a month for water. I want to do it as a conservation method and to just have a bit of fun. Don't tell my wife; she is against it.

    Bookmark   December 26, 2013 at 10:26AM
Sign Up to comment
More Discussions
KNNN espalier planting
Hi - I just planted some 1 year bare root apple trees....
Jamie Cartwright
what kind of fruit tree is this?
My guess is some type of peach, but the fruit is throwing...
Converting typhoon damaged hillside forest to blueberry plantation
Hello all We've recently obtained a small strip of...
conflicting pawpaw spacing info
Last week I planted several dozen paw paw. I had read...
Bushwhacker Blood
Jujube plants from roger
I would like to have jujube shanxi li. I know roger...
© 2015 Houzz Inc. Houzz® The new way to design your home™