Yes the whole house filter could be clogged.
our water pump get its water from the tank, the city water comes thru the whole house filter.
our fill valve must be in the closed position to get city water into the house system.
does your tank fill have a automatic shut off ?
2000 Newmar mountain aire 4081 DP, ISC/350 Allison 6 speed, Wrangler JL toad.