I'm not sure, since I bought my hose from a RV supply place, not from Mr Heater. But I assume, from their manual, that you always have to buy the filter separate. And I have NEVER seen a filter in a store, so I guess you have to order them from the company, or from a supplier on e-bay (where they seem to be a bit cheaper). I ruined a Big Buddy by not using a filter (didn't think abuot the turning the tank off first thing)...