Selling Property cost of transferring water registration

[alig99]

Hi all,
I wonder if someone could clarify costs of transferring water bill to new owner. A friend has just accepted an offer on their property in Canillas de Albaida and have been told that the Ayuntamiento charge for doing the transfer is 6000 euro, yes 6000 euro! Apparently Competa charge a mere 800 euro..... How can town halls justify this or is this info incorrect? Can this charge be challenged? we feel this is highway robbery!