We had a phone call from the water authority. They had taken the trouble to find someone who spoke English in order to call us.
They were concerned about a sudden increase in water consumption during December and January and were worried in case there was something wrong with the water meter or perhaps a leak somewhere. Should they send someone out to take a look for us?
We explained that we'd had many visitors over this period and therefore, yes, water consumption would have been increased substantially. They understood and thanked us!
Another little bit of Japanese culture that is just amazing.