We usually use about 10 cubic meter of water every month. I received a phone call from my water company said that we used about 16 cubic meter of water per month in the last 6 month. So I monitor the water usage and it seems to be normal (1.2 units in 5 days) Then we went to holiday for 6 days and water meter went crazy! We used nearly 21 units in about 6 days when obvious no one used any water! I checked the tap, toilet, garden hose, wash machine, dish washer, central heating and no trace of water marker of leakage. I turned off the main valve in the house and the water meter didn't move at all. Now I am confused because the meter reading is so sporadic, any suggestions?