Unless marinas have received planning permission for residential boaters then you do not have to pay council tax. However, a lot of marinas do not and to get around this legality, the marina owner has the opportunity to move boats around and this stops charges. Some marinas don't have many facilities, this is taken into account too. The council generally target people on benefits to pay council tax if you are on a mooring, this can be resolved by going to the valuation office agency. One councils rules may well differ greatly to another.