I've had a few people asking about the rainwater harvester on my allotment in the village, and specifically how it was put together. Like many others I'm sure, I couldn't really bring myself to spend £35-£60 on a water butt that could only hold 210L. Similarly, whilst I'm only about 5 minutes walk from home it didn't seem right to be walking to and fro to water my plants with tap water.
This is where I came up with the idea of using an IBC container. These are 1000L containers, many of which transport food-based contents such as food extract and once they have been used once, they're surplus to requirement. You need to make sure that the containers are food-safe because there are some of course which are used to transport oil and fuel-based liquids.
There are companies which sell second-hand containers online, but personally I used Facebook Marketplace (https://www.facebook.com/search/marketplace/?q=ibc%20container) and found a container locally which cost me £40. They come in 600L and 1000L varieties, and usually with a pallet on the base. Many suppliers sell tap and hozelock adaptors to fit on the front also which is just what I was looking for. My plan was to use gravity-fed pressure to drip feed my plot on a timer.
The frame was quite simple to build, with the appropriate slant for the roof, and sufficient width to support 3 full size corrugated plastic roof sheets.
The posts and support were all purchased from Mole Valley, and pressure treated to provide some longevity. Whilst it wasn't necessary I decided to concrete in the posts for extra support as I didn't really want the frame collapsing in the winter weather.
Here's the finished product with the guttering and roof fitted. Total build cost was around £85, however holding 5-10 times the amount of a standard off-the-shelf water butt it was certainly worth it. With 3 full-size sheets, I managed to collect around 250L with 3 days of showers, so I'm certainly happy with the final product.
There's enough room for another 600L IBC should there be a need to expand, then they can simply be linked together.
I hope that was a helpful tip for those of you thinking about how you can harvest some of the free water that we get from the elements. Happy to provide any contact details of where I sourced some of the materials from if needed.