DIY: Build A 3 Drum Rain Collection System, Very Easy & Very Cheap

1I live down in south Louisiana and plant a vegetable garden every year.  Now even though my area is considered tropical, we do have dry periods. Watering my garden  from the tap hinders the growth because of the chemical and algae inhibitors that they add to make it drinkable (potable). (not to mention what the “crooks” at the water dept. want to charge you!!) Any nursery or avid gardener will tell you that tap water is not the best thing for your garden.  When it would rain my garden shoots up 4 inches overnight!! (dramatization).  So I began searching for a way to capture and store all the free water I wanted.

I looked at plenty of designs that used the vertical placement method. You’d better set aside a lot of landscape to set up that way,  but with all of them you have to drill vent holes or cut large fill holes and I didn’t want to destroy my drums like that. With the stacked system there is no pumping needed. Everything is gravity fed. (and pretty good pressure to boot)

First of all let me clarify for the grammar nuts: these drums are layed horizontally, and stacked vertically.


1) Simpler design and easier to build.(approx. a 12 pk. job) A horizontal “stacked” system takes up much less space than placing them side by side vertically. Great if you don’t have much room to spare. (go up rather than out!)

2) I removed the tilt of the barrels. Unless you cut/drill vent holes in each of the barrels, they will only fill to about 75%. I want to utilize the maximum amount of storage from these three drums. Being level, they should fill to about 95%, plus if I decide to dismantle the system and use the barrels for something else, I have that option since I haven’t rendered them useless by cutting or drilling holes in them.

3) I changed the installation to a much less permanent one. Instead of digging holes and cementing it in, I will mount the system on concrete blocks (think I paid $2.59 each for them), in case I need to move the system or use the drums for another purpose.


4) I implemented the “cradle” design which makes the drums part of the supporting structure. This way I do not have to use 4×4’s to bear the weight of three full drums. The 2×4 legs are basically there to hold the whole thing together and for bracing.

5) Rather than use expensive (and hard to cut) 4×4’s….I used 2×4’s. It is still as strong as a 4×4. Its just the reinforcement that matters.

6) Kept metal out of the system completely. (which doesn’t matter if used for rainwater anyways)(comes in handy if I need to convert this to my SHTF fresh water supply, or I will use my aquaponic system. Yep…I’m a doomsday prepper.


With the horizontal mount you don’t have to worry about cutting unneeded extra holes in your barrels therefore destroying them. The top drum vents the entire system via the hose connections (see video) as well as making the whole thing essentially one tank.

Once again, this doesn’t involve any cutting of the barrels that basically render it useless if you decide to dismantle it and use them for something else down the road.


First of all I cut my cradles that will be used to support the barrels. I simply traced the outline of the drum and cut from there. I cut ten of these. With this design I should (and that a very strong word) should be able to stack three for my system.


I used 2×4’s for the legs. Now you might think this may be a bit flimsy for supporting 3 filled 55 gallon drums (approx 500lbs each.) but the cradle pieces between the drums are part of the support themselves. The 2 x 4’s are basically there to hold the system together. (of course….I’ll test it to just to make sure)

Assembling the system and installing the drums. the plywood on the sides is for bracing, eliminating any sway from front to back. The cradles will brace any side to side sway.
I will also test the system to ensure that the cradle system & 2×4’s will handle the weight.


Pretty much adding the plumbing to the drums. My drums had threaded bungs on both sides which made this design possible.
I found these nifty little gray 3/4″ NPT angle fittings that connect the drums at Highs (lowes). They do the trick nicely and only cost about $0.89 each. (much cheaper than brass hose fittings)


Testing the system. I filled the water on the top drum and it vented nicely down to the next two drums. the video shows one of the connector tubes as the water traveled down and the venting process occurred at the same time. Performed rather well, I think!


Finished system. The drums as well as the 2×4’s supported the weight nicely. I can now drain it & disassemble it so I can treat the 2×4’s as well as paint it.
I will add the inlet from the gutters later, but it will simply pipe my gutter to the upper hole on the top drum…(see…still no cutting of the drums!!)


Here is a video of the system filling from the rainwater.


Here is a video showing the water  migrating from the upper drum to the lower drum and at the same time theair venting upwards. (the connection acts as a vent as well, see….no vent holes drilled)

: After about a half inch of rain yesterday and collecting only about 20% from the gutters my system has filled to capacity! I may keep the crude collection system because you do not want the rainwater entering the system at a rate that’s too fast for it to settle to the bottom drum (gets top heavy) I guess it all depends on how much rain you actually get.

If you only get a half inch or so every month, you may want to collect every drop you can, but I’m in a rather tropical area, so its not as critical for me here.
Its no secret…..this is a dual purpose unit. I am a doomsday prepper and this will be used as my freshwater source if the SHTF. But until then it will make an excellent vegetable garden water provider. Also a suggestion was made about piping the top holes together and the bottom holes together for easier fill during heavy rains. This is an excellent idea. The amount of sediment, dirt, bird fecal matter and general BS&W that washes off of the roof?  Not a problem if your just watering your garden, big problem if you are reclaiming for drinking…..YUCCHHH!!!  Soooo…..I added a small riser to the inside of my gutters outlet. This prevents any heavies from entering the system. A good suggestion is to let it rain a few minutes before you connect your collector. LET THE CRAP RINSE OFF OF THE ROOF FIRST!!!




by cajundood


4 Replies to “DIY: Build A 3 Drum Rain Collection System, Very Easy & Very Cheap

  1. Hi there, I came across this after having had the same idea myself so it was a real great find to see you have already made a working one!
    I have used the same principles although I slightly improved the piping to help the air escape the barrels better.
    Additionally, I have a total of 9 barrels in a big rack, stacks (or columns) of 3 side by side, at the moment just 6 connected but eventually all 9 will be.
    Once the first column of 3 has filled it overflows into the next column, and the next, you could probably add as many as you like.
    I would love to share my photos and video of my system with you, let me know if you want me to send in the files.
    I built walls and doors around my rack and now call it my WATER CLOSET!
    Thanks for the inspiration and advice!

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