Colin's rain-water toilet

Colin turning on the tap for the first time

It all started because I had a length of 10mm copper pipe left over from the solar water heater. We did a toilet usage survey and found that we flushed the toilet about 4 times a day: 8 litres each time: 224 litres/week or around £37/year. A £33 garden water butt holds 220 litres, enough for a week's use. The drainpipe outside the bathroom had a 22m² catchment area. The monthly rainfall for Oxford is roughly constant at 25"/year or 1.2cm/week. That is 270 litres/week for our catchment area. If the rainfull was uniform and if we collected it all, we should be self sufficient. Plenty of ifs! We should need a mains water backup. Filter 1: a kitchen scourer

A downpipe was conveniently near the bathroom, but if pumps were to be avoided, the rain butt needed to be elevated well above the cistern height. James' new garage doors had just been installed and the old frame was ideal. Filters seemed a good idea, so I used first a stainless steel pan scourer placed in the inlet to the rainwater downpipe. Secondly I used a kitchen seive, glued over the tap inlet. The two ball valves in the cistern The finished toilet The 10 mm diameter copper pipe went through the bathroom wall, under the bath, then along the bathroom wall under the carpet till it surfaced below the cistern. I insulated it with exposed bits of pipe as the very cold water from outside tended to cause condensation on the pipes. I needed to buy two slim ball valves, one for the mains water and one for the rain water each with a control tap. They fitted into either side of the cistern and worked well with both water pressures. At the time of writing after a month's use we have not had to try the mains water. It fills slowly but silently.

A problem soon encountered was the difficulty of knowing the level of water in the butt. I had to fetch the step-ladder, climb up, open the butt cover and peer in. I devised an electronic level meter. The LEDs embedded in a tile glued to the wall The resistance sensors inside the butt When I connected up a LED in series with a 12V AC source and made the circuit through the rainwater I had not expected to see anything, but it did light up dimmly. I made a set of 5 pairs of contacts from screwfix screws glued into a plastic cover which dipped into the butt. By chance I had a long length of 6-core telephone cable which was easy to thread into the loft from above the butt. From there it went to the transformer and down again into the airing cupboard which was next to the bathroom. The picture shows the 5 LEDs mounted into a tile. It all works just fine.