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Rainwater Cistern

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This is a cistern I made from some pressure treated 2x6 material and a 55 gallon plastic juice drum. I got the used drum locally for $15 and the wood came from my scrap bin.  I chose to use 2x6 material because I had it handy, but if you choose to use 2x4 instead, some dimensions will change.  I haven't done any structural calcs, but the water weight alone of 55 gallons of rain will be about 459 pounds, so keep that in mind if you change the size.  I use this to water my vegetable garden which is nice and close to the cistern.

To make this, you will need:
  • Aa 55 gallon plastic drum with the screw caps intact
  • The following pieces of 2x6 pressure treated (PT) lumber:
    • (4) 28.5"
    • (7) 24"
    • (4) 23"
    • (4) 18"
    • (2) 13"
  • Construction adhesive
  • 2-1/2" all purpose fasteners
  • (3) 2" PVC 90 degree elbows
  • Small lengths of 2" PVC
  • 3" to 2" PVC reducing bushing (to attach to your gutter's downspout - your application may vary)
  • (1) 3/4" PVC threaded male adapter (to attach to the barrel's cap)
  • (1) 3/4" PVC 90 degree elbow
  • (1) 3/4" PVC shut-off valve (controls the flow of the rainwater when you use it!)
  • (1) 3/4" slip x 3/4" MHT PVC fittings (this is at the end of the pipe exiting the barrel - you can attach your garden hose to this)
  • (1) 2" PVC coupling (this will form a riser to keep sediment out of your garden water)
  • (1) 2" PVC male adapter
  • (1) 2" PVC female adapter
  • Epoxy
 
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Step 1: Get A Leg Up

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Start by glueing and screwing 2 lengths of 2x6 together, keeping the bottom end flush.  They are 28.5" and 23" long, respectively.

Step 2: Two Legs Are Better Than One

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Repeat step 1 to make a built-up second leg.

Step 3: A Time To Join

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Next, cut an 18" piece of 2x6 and glue & screw it between 2 of the legs.

Step 4: Have A Pair

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Now repeat steps 1-3 so you have an identical U-shaped assembly.
trouse11 year ago
Need barrels?
I found that at the $2 car wash they have 55 or 60 gal drums that contain the soap that's used in the wash cycle . If you don't mind the work of cleaning them thoroughly, they can be had for little or nothing. I pick them up setting by the trash dumpsters at the car wash. AFTER asking if I can have them.
RushFan (author)  trouse11 year ago
Excellent suggestion!!
Stavros!1 year ago
ah, that's right, you've got a big hole in the top of your barrel, I forgot about that. I've got the pvc inlet screwed into the bung hole, so that's different than your setup. With a "t" on my pvc inlet, it lets the barrel fill up, and the overflow is piped away. Here's what I used on the first barrel, and when I got the second barrel I used a "t" on top of it to fill the second barrel and be the overflow.
rain_gutter_diverter_lg.jpg
martind171 year ago
No screening for the water entry?
RushFan (author)  martind171 year ago
Yeah, I have since decided to wrap a piece of fiberglass screen around the inflow pipe and spread out over the top of the barrel. I will edit the instructible and add a photo.
Stavros!1 year ago
I disagree with this set up. Don't drill the side to put in an overflow, use a "t" fitting on the top where the inlet is, and from there plumb to the drain. Why drill extra holes in the rain barrel, and reduce the capacity of it at the same time?
RushFan (author)  Stavros!1 year ago
If a tee is used above the top of the barrel, the barrel will overflow before water has a chance to reach the tee. My outflow is 3" from the top; that represents less than 6 gallons. If this was for drinking water for my family in an emergency, I might be concerned. For the plants, I don't really care much for the 6 gallons. :)
IOPort511 year ago
how did you get the female adapter into the drum to thread to the male adapter?? I think I could drop it through the fill hole but holding if to tighten may be a problem.
RushFan (author)  IOPort511 year ago
Great question. I made the hole in the top (for the inflow) large enough so I could reach my hand in and hold one while I turned the other.
Also, be vary of Bisphenol A and similiar phthalates in the plastic components that could contaminate the water. That stuff can imbalance your hormone level or even make you infertile. Make sure the material doesn't degrade from UV light or feel softer than it should.
criggie1 year ago
I have something similar - just used an old steel lab stool as a stand. The main problems are

* Lack of pressure - need to raise drum high as possible, connect it to a drip feeder watering system, use a pump for pressure, or only fill watering cans.

* Leaves in from the roof - a screen helps but still needs to be cleared off periodically

* Related - green snot. I drain my drum in mid-winter when its not really needed, and there's routinely 50mm of mud and smelly brown mess in the bottom. So remember to clean it or the outlet port and overflow ports may block up

* Mosquitos - little blighters love to lay eggs in stagnant water. So seal up around the inlet - some foam rubber wedged in would be fine, or even some duct tape.

* And finally - emergency preparedness. We had a 7.4 a couple years ago and my full drum moved on its base. Consider where it might land if a quake knocked off the whole device.

Note the water stored in this is generally not drinking quality, you'll absolutely want to boil it clean before human/animal consumption. Its fine for plants.
Stavros!1 year ago
No, there's a male adaptor pvc fitting that will screw into the bung hole, so you don't have to drill a hole. Plus that makes it watertight, and bugs can't get in, as long as you've a screen at the top of the pvc opening.
nmcrae11 year ago
I've got a similar setup, but with a piece of fiberglass window screen to keep out the sediment, and keep the skeeters from getting in there to breed.... I've got 2 barrels attached to a low pressure drip irrigation system (from Lee Valley tools) and it works GREAT! I almost never have to use tap water for my plants.
maewert1 year ago
I think the diagram in Step 8 shows the top slats at 90 degrees from how you built it (looking at Step 9). How you built it in step 9 appears to be stronger than the diagram in Step 8. Just rotate the diagram slats and you're good to go! Thanks for the 'ible!
Best Wishes
IamTheMomo1 year ago
Oh, please tell me the name of some place I can buy this drum that inexpensively! Going 5 days without water after a hurricane was 4 days too long!
In our area there is a pickle barrel seller (55 gallon) who offers them for $5 each. Craigslist is a good place to look for your specific area. I paid $15 for mine before I found the $5 guy!
RushFan (author)  IamTheMomo1 year ago
I wish I could help! If you are in the US, give craigslist a try. That's how I found my $15 barrels, and it was nice and close.
horphmyre1 year ago
I had purchased a plastic base to hold my drum. During the summer when the drum was full of water, the base buckled and threatened to dump my barrel over, so I empltied it. A couple of weeks ago I made a base out of 2.4s. i measured the bottom of the barrel which was 15 inches and cut several pieces of 2X4 and nailed them together at the ends, until it was 10.5 inches high and then added two more for the inside of the top. This one is not going to buckle. It doesn't look as nice as yours, though.
chrwei1 year ago
does this provide enough flow for you? around here I've seen a 3x4 downspout gush like a firehose, so I'd be concerned that the 2" pipe would constrict too much cause the gutter to overflow. My in-laws just installed a 250 gallon container, and with the last heavy rain they filled in 30 minutes from just half their roof.

also, you're going to get a lot of debris and sediment in your barrel without a filter, maybe not if you don't really have trees tough. and if you have mosquitoes in your area at all, you're going to want either a screen on that hole or seal it up some so that down the spout is the only entry.
RushFan (author)  chrwei1 year ago
Thanks for the comments chrwei - the flow seemed fine the first time I tested it. I live in Florida and the first rain after I installed it was quite heavy. Of course, I was out there watching, getting soaked. There weren't any back-flows, or overtopping of the gutter. There are no trees very close to the roof, and the gutter has screens to stop any leaves that do blow over. As for mosquitos, we get enough rain that there will be regular movement through the barrel. However, I have already devised a plan for wrapping the inflow pipe with screen, and then securing it to the top of the barrel - just in case I need to.
chrwei1 year ago
I found a shelf calculator http://www.woodbin.com/calcs/sagulator.htm that should be of some help.
since this isn't exactly a shelf you have to do some fudging. if you have 2x4's (1.5x3.5 actually) in a square, you basically have a 3.5" thick 6" deep shelf. I chose "center load" since that's a worst case, and at 24" span it gives 0.01" deflection, which is pretty good for a worst case since it would to be more than 4 times that to even see the sag.

at one time I'd found another calculator and did the math for the uprights, and concluded that 2 2x4's 8 foot long would be able to hold up 1 barrel full, as long as it was completely stable (somehow). so, a couple feet long and 1 on each corner is plenty as long as you can secure them so it won't wobble.
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