We have experienced sudden decreased pressure in all outlets of the house. The home and well is only 5 years old. The decrease is in all sinks, showers, etc. We have changed the water filter and checked the pressure in the water tank. What should we be checking?

If the pressure is fine at the tank, obviously there is a restriction after that...

Check the valves? Has any work been done recently? Sometimes the whole-house valve or post-filter valve does not get opened all the way up following work...