Friday, August 04, 2006

Rainwater harvesting – Part 2. In our blog of 8th July I talked about our "cobbling together a budget solution" for a rainwater catchment tank but that we had yet to choose a filter. Of choice, we would like to have bought a WISY downpipe filter but it just proved too expensive for our budget. So, in keeping with the rest of the system, our filter was assembled, with a bit of imagination and ingenuity, out of a variety of components.

First off was a cheap plastic downpipe collector sold for use with standard guttering and garden water butts. This has a rudimentary filter that will strain off particles larger than about 3 x 3 mm and a diverter, which can send all the water down the drainpipe, useful in winter. I attached some large-diameter hosepipe to this, leading into a small plastic bucket, which was a tight fit over the inlet to the tank. Inside this was a fine-mesh basket used for planting in ponds (also a tight fit) which I lined with some hessian sacking. I hope that this will strain out any remaining particles and I will rinse out or replace the hessian as appropriate.

With the aid of a ladder and watering can, it’s tested and works and so we are just waiting for the next rainfall. I’ve also installed a standard 300-litre water butt in the garden of our holiday cottage. When I re-roof the barn later this month, I’ll install another butt there too. As I’ve said before, for a really informative and pragmatic approach to all things watery, I cannot recommend Judith Thornton’s book The Water Book highly enough.