According Southern Water's own website, the estimated ANNUAL metered water bill for a family of 4, using water for all the usual purposes (such as personal hygiene) plus watering the garden, washing the car and using a dishwasher is £572.47. That equates to £143.12 per quarter:
https://www.southernw...s/wouldYouBenefit.asp
Metered water bills vary widely, depending upon whether or not people follow water-saving measures (such as only flushing the loo when it's really necessary and then using the water from their shaving bowl to do so). My own bill (for just me, with no dishwasher and using the laundrette rather than a washing machine) averages around £15 per quarter.
Chris