Look into the port the water gushed out of and see if there is something jamming the check valve disc open. It's not the pump. The check valve in the city water connector is stuck open or damaged. That's probably a lot cheaper than the pump, which sounds like it's working fine.
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Rich, KE4GNK/AE, Overkill Engineering Dept.
'The Silver HamShack' ('07 International 22FB CCD 75th Anniversary)
Multiple Yaesu Ham Radios inside and many antennae sprouting from roof, ProPride hitch, Prodigy P2 controller.
2012 shortbed CrewMax 4x4 Toyota Tacoma TV with more antennae on it.