You have a problem somewhere in your system. That is way too high for an average family. Believe me, I have lived in a house with 5 people who has no sense of saving energy, use dishwasher every night, washing machine 5 times a week etc. Still our water bill was maximum about £60.
No problems apart from we use a lot, are you saying your bill was £60 per month, how long ago was this, what area, our washing machine is 14 times a week.