Have you ever used well water?
Perhaps muddy well water from a low well clogged your input filter screens. There is one in the city water inlet and a large screen pre-filter on your water pump.
Removing your whole house water filter completely should have fixed your troubles. Since it did not you will also need to pull your aerators in the sinks and shower and see if they are blocked with scale.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW