Plumbing 55-gal. Plastic Barrels for Water Storage

Why Barrels?
- common waste product
- may be available free
- strong, lightweight, durable, good on water quality

Several types of barrels
removable top/"open-top"
- can be re-used in many ways (compost turner?)
- rarer around here
- more expensive to buy new

"Closed top" barrels
- used fo the design below
- more common
- cheaper to buy new
- fewer re-use possibilities besides liquid storage
- no removable lid, just two threaded holes:

The best barrels for water storage have only held food products, like cola syrup, grain/baking supplies, juices, sauces, animal feed?

On the other hand, this design calls for many PVC joints (see below), meaning many fittings and much time spent fitting them. The price of the PVC fittings may greatly exceed the cost of the barrels. The time required to plumb more than a few barrels may be prohibitive. Fortunately, the design is fully scalable, all the way down to a single barrel.

This system is intended to be connected to a house gutter to provide rainwater storage, ultimately feeding an irrigation system for a garden plot.

On Bungs
Closed-top barrels usually have two threaded holes, one coarse-threaded, the other fine-threaded.

Coarse thread hole/"bung"
- funky threading: buttress threads
- but: bung cap has an adapter for 3/4" NPT

Fine thread bung
- regular 2" NPT female threads

Bung caps are made to accept a bung wrench for opening and closing
You can buy one or you can make one.
A pair of pliers will work in a pinch.

Barrel Support
Weight of water is an important consideration.
Water weighs eight pounds per gallon.
A full 55-gal barrel weighs more than 440 pounds.
Some barrel system designs require the construction of a sturdy timber frame for stacking the barrels. This is a fine idea if you have the necessary time, resources, and expertise. I do not.

Instead: stacked barrels in a pyramid--cheaper, faster to construct, more mobile, less resource-consumptive than timber frame.

- Avoid crushing empty barrels. Full barrels shouldn't sit on top of empty ones.
- Prevent the barrels from rolling away when full. Wire rope wrapped around the barrels like a giant rubber band might work
- Prevent the barrels from blowing away in the wind when empty.
- The higher the barrels are, the greater the pressure at the outlet. Might want to make a base from something sturdy. For more, see this.

Plumbing the Barrels

Scale up/down to suit.

One feature of this design: the nominal distance between any two connected bungs is ~23 inches (diameter of one barrel).

Why is This "Untested"?

We found a local source for IBCs at $20 each, cheaper than plumbing the comparable number of barrels. (2 IBCs = ~600 gallons for $40).
We've had a hard time finding suitable barrels for free in the Richmond area.
Faster to install 2 IBCs than 10 barrels.
But, I couldn't find anything on the intertubes about this.

Related Reading
Art Ludwig, Water Storage: Tanks, Cisterns, Aquifers, and Ponds
Stacy Pettigrew and Scott Kellogg, Toolbox for Sustainable City Living: A Do-it-Ourselves Guide


ccm84 said...

Awesome idea

Craig Spakowski said...

one small hiccup i noticed. unless the barrels are vented they won't fill. you need to connect all extra holes with a similar system to allow em to vent

Diggity Dog said...

Personally, I'd be nervous stacking 2 IBCs on top of each other without some serious metal strapping or something along those lines. 275 gallons at 8.3 pounds per gallon means roughly a ton of weight per tote.

Also, It depends on how tall your house is. I have a single story home and if I stacked 2 totes, then they'd be higher than the gutters.

Anyhow, I'm working on setting up one tote at this time. Having a hell of a time finding 2" female fine threaded adaptor to a garden hose fitting. I suspect I'm going to have to just rig something up myself with a flex to PVC connector.

Diggity Dog said...

Two things. a) I need to apologize. It wasn't until I read more of your blog that I realized you're sufficiently technical that you already knew you'd have to stabilize the upper barrel. Sorry for being condescending.

b) Turns out I was wasting a lot of time online looking for the 2" female threaded adaptor when I just needed to stop by Home Depot or Lowes. I've got my rig put together and the PVC cement is drying now. Hopefully I'll have it up and running tomorrow. Then I just need to decide on a pump to drive the sprinkler I'll be using in the garden.