Six-barrel Rainwater Storage
300 Gallons of Rain Water Storage

Part 1 of Building a Six-barrel Rainwater Collection System

Rain barrels are a fantastic idea. Not only will they save you money, most houseplants love rain water (especially spider plants, it will keep them from getting those brown tips). You can also use that soft water for young seedlings or anywhere else in the garden. But we have a fairly extensive garden with lots of fruit plants and a small orchard, and 50 gallons of stored rain water doesn't stretch very far. We're going to need a bigger barrel. Or two, or four, or even six!

How We Built It for Less Than $150

There is a shed in one corner of the yard with a narrow space between it and the fence. This space is useful for storing lumber but inconvenient to access, so we're going to place six plastic barrels there instead, and they will store three hundred gallons of rain water.

One side of the shed roof will collect the rainwater. We would prefer the system to manage itself, so we will also incorporate an automatic overflow to dispose of the excess water when the barrels are full. But we will also want to keep this low tech, which means no moving parts except for the faucet.

How much rain will we need to fill the multiple barrels? An inch of rain collected on one square foot of area will produce 0.63 gallons of water. This side of the roof has a collection area of 80 square feet. That means an inch of rain on this roof would provide 50 gallons of water (80 X 0.63), and six inches of rain would fill all six barrels (80 X 0.63 X 6).

Update February 2015: The system is working very well. Over the past five years there have been a few mornings with temperatures in the twenties but there have been no problems with the system. It is working exactly as anticipated. We would not change anything if we were to build another one. We've flushed (emptied) it twice at the beginning of the rainy season.


Shows space between the shed wall and the fence.Enlarge image

Here's where we're going to put the system, in roughly a four foot by fifteen foot space. There is a french drain underneath that gravel because of our high winter water table.


Shows the barrels placed on the ground.Enlarge image

Before we build the platform we'll do a test fit: looks like there will be plenty of room, so full speed ahead! Let's work on the barrels. Lots of pictures!


Page 1: Introduction (this page)
Page 2: Putting together the rain barrels (lots of pictures!)
Page 3: Finishing up with the rainwater collection system