The River Severn rises in mid-Wales and flows into England towards Shrewsbury, where water is extracted for drinking. In return, the Severn receives the treated effluent from the town's sewage plants. (I was pleased to see news of a £14m scheme to improve the quality of the effluent.)

The process is repeated at Bridgnorth, Stourport and Worcester until the Severn reaches Gloucester, where the system is varied. The water is pumped up from the river into Gloucester Docks and then flows along the Sharpness Canal to Purton, where it is extracted, treated and pumped into storage reservoirs for our taps.

The water is quite palatable, although there is a distinct chemical aroma when the cold tap is first opened in the morning.

For drinking, we keep a litre jug of water in the fridge - this eliminates the chemical aroma. We don't use bottled water. Seeing the environmental damage in Peru and Nepal from use of bottled water by tourists finally convinced us that plastic bottles are an environmental disaster.

Phil