I might have some wrong settings. but when I was using the city water connection the tanks filled to capacity and started overflowing while in the past, I just hooked up the hose to this same port an we had city water to use w/o filling the water storage tanks.
A possible difference--the flow regulator may not have been at the proper setting or it may not have worked. secondly, when I used the water from the tanks the small pump would not sufficiently charge the lines to ever shut off so we used the switch to get some water flow to the sinks and shower but with very low pressure.
I did not see any leaks in the water lines. But could there be an air vent or valve that needs to be closed or turned another way?