Hi Maya,
Did he show you the actual bill? In our area it is only for a 3 month period - and even then it comes 6 months in arrers!
If you are able to visit the offices (or maybe they even have a website?) of said water co - I got a chart listing the actual cost per cubic litre. It is common to get the first 20 cubic litres for a small sum - around 14 cents per cultr? It then goes up to a higher band for use in a month over that, then again and again.
The largest bill we ever got (2 people 24x7 occupancy of a small campo finca - but we had to water the garden 4 times a day one summer - so a lot of water!).... was Eu150 for 3 months.
I think the landlord is trying it on.
I think you are familiar with the ‘system’ here and if you have any complaints/concerns you can go to your local consumer office.
Was there also a rental contract for the short term let? What are the writtern Ts&C’s.
If the bill is accurate (and he is not watering his veggies/garden too!).. then yes, it is possible there is a leak somewhere.
But as you say… why should you cough up. It is his responsibility!
(NB An ex landlord where I only paid rent and no bills thankfully - His water bills were around Eu400 for 3 months - as he watered the lawn twice a day all through the summer!).
Is it a private water co/urbinization (which usually set their own tarrifs), or a local company.
Good luck. sj