How costly is it to keep your garden watered? Find out and control it.

Much water has "flowed under the bridge" since the author's original Digital Water Meter was published in EPE June 1994. Indeed, in many parts of the UK, probably far too much has flowed this year! Interestingly, that meter was designed at a time of great drought in Southern England and there were concerns that water should be conserved for ecological reasons. This too was a time when UK households were in the process of going over to paying for water by quantity used rather than according to a fixed annual charge.

Terry de Vaux-Balbirnie tackled one aspect of garden watering consumption with his Hosepipe Controller of June '01. His design allowed watering to be automatically cut-off after a preset period. The Water Monitor presented now also allows preset water cut-off, but has the additional benefit of actually telling you the cost of the water that has been used to keep the grass green. The design is PIC controlled and includes a 32-digit alphanumeric liquid crystal display (l.c.d.). The Water Company's charge per cubic meter of water used is entered via pushbutton switches and is automatically stored for future recall. The l.c.d. shows the elapsed time since watering started, the number of liters used, and their cumulative cost.