[Unicum] water meter

Hi,

Our water consumption  is usually about $60.

Surprisingly, our most recent  bill ,received last Friday, charges $540.

In the previous period our water usage was the  same as it was before or even less, and we did not use our garden house to water plants either. A check of the water pipes and appliances showed no leakage or malfunction of any kind.

Anyone has some suggestion as to what might have happened and how to avoid it?

Thanks

Vince