All our filters are done in the washing machine. A full drum every day. Certain ones have to be done with the pressure washer first, but one way or another most of them go in the washing machine with a little bit of antibacterial liquid (can be bleach, can be disinfectant, can be whatever is on offer at Makro or Wilco etc.) along with the soap powder.
Same goes for all the back hoses. Mix them in with the filters why not. We usually wash hoses on their own, but sometimes filters get mixed in with them. Occasionally the odd one will come out destroyed but maybe it is 1/100 so we shrug our shoulders and replace that one with a new one.
If you are doing a proper job, I think it is good practice to put back hoses, internal hoses and filters through the washing machine.