City inlet is a check valve, Two things you can do.
NOTE: the first will get you wet.
Turn pump off, REmove screen washer from inlet.
Turn pump on Water flows, there is a small white "pin" in the center o the outlet.. Push it, gently.. NOTE: some say you do this the valve will never work again.. This may be true but since it is not working now, what do you have to loose? (A dry shirt of course).
If it seats when you release it, Flow will stop and all is good. If not.
A plug will work for now.. and replace the inlet when you get a chance, easy job.
Home is where I park it!