12 v water pump possessed?

it's right at the hose connection. If you have water available try hooking up and turning on the hose to open and hopefully seat the valve

Hi,

Most commonly the shore power water connection has a back flow valve. Sometimes they stick. I believe there is an "O" ring that may have aged out.

Use a plug.

One of my rigs had a petcock to shut off city water from the inside. If you have one and it's open, then water could be shooting out.
However, there should be a check valve in the city water connection that does not allow back flow. Maybe check that too.

Yes there is one in the connection This Video may be of help to you.

Until I got mine fixed I used a Plug as in the video.