To get at the check valve you may have to remove the surrounding hatch.
A day can create quite a mess, a week even more of one.
The air pressure on an empty tank should be 2 psi below the pump's cut-in pressure.
A few things come to mind: a burned out water pump fuse, a broken wire to the water pump, a bad water pump switch or associated wiring or a bad water pump.
When the city water is connected, water on, faucets open, no water comes out anywhere.
If I run out of water, can it damage my pump? Really the only way to find a leak is trace the water and check all of the plumbing in the area.
The shop told me it was the full-coach water filtration system that made it so slow.
Some Final Comments Water pumps are nothing to be afraid of.