Here’s my DIY rainwater harvesting & storage setup. Rain water is stored in the 4 water butt’s and the 1500 litre storage tank. Got lucky with the tank, It’s an old one and cost just £20 from another plot owner who never got around to using it for over a decade. Just £20! A fraction of the cost of a new rainwater tank. All this rainwater storage may look a bit like overkill for the size of my plot but I have heard that even the allotments have not been immune from the occasional hosepipe ban. That would mean a lot of trips to the tap with a watering can in the height of summer!
To harvest the water I’ve fitted guttering to both the shed roof as well as the greenhouse. The rain water from the shed goes into a water butt for storage and there are another 3 water butts conected in series to it, each one a little bit lower than the last to enable the over flows to work. Here’s the water butt setup.
I fitted the large rainwater storage tank to collect water from the larger area of the greenhouse roof. I had to dig it into the ground about 20cm so it would be low enough to allow the rain water to run into it. It had an old cut off fitting at the base which I sealed up using a DIY fiberglass kit. It seems to be holding as the barrel full of water I put in to test it never leaked out. I hope it holds under the pressure of the increased head of water as the storage tank fills up. As a temporary fix I used a bit of guttering to transfer the water to the tank and used a cheap plastic kitchen sieve to filter any leaves etc.
I’ve just got hold of another large water butt on freecycle. Just a fast DIY job to repair the tap to stop a leak. It will become the overflow for the large rainwater storage tank but I don’t need to worry about fitting the water butt for quite a while, especially as we’ve had the driest & warmest April for a few years. I’m looking forward to it raining so I can harvest the water to use throughout the year as plants seem to perk up a bit on a diet of rainwater compared to tap water. I’m thinking I’ll still need to rely on the allotment tap a bit this year unless we get quite a bit of rain soon. The blue barrel in the picture above will become part of an irrigation system for my allotment plot but thats still in the planning stage at present.
(update 8/5/15) In an effort to harvest more rainwater I rigged up a tarp, tied to my grapevine posts and a tree, to increase the surface area available. I can now put up or take it down my DIY extra water capture setup in about 5 minutes, handy for when I know to expect some rainfall. A half brick creates a centerpoint for the rainwater to run to and then it drains into my unused water butt.
I’m now hoping for enough rain before summer to harvest enough water to enable me to avoid using the allotment tap. The other tarp on the floor is to cover the grass & kill it off a bit before I create more deep beds. I’m also thinking of putting in a small pond, not so much for water storage but instead to attract frogs and anything else that likes slugs and other pests.