City Water connection squirting out fresh water inlet
I was camping this weekend. My fresh water tank was empty from previously sanitizing and draining it. I hooked water to the city water connection thinking I would just run off of the city water without filling the tank. I ran the hot water for a little while to make sure the hot water tank was full before turning on the 110 HW heater. A while later I went out side and noticed water squirting out of the fresh water tank inlet. I turned off the city water and looked at the fresh water tank. Low and behold it was full.
How is water getting from my city water connection into my fresh water tank? Have I opened a valve between the two when I was sanitizing the system not meaning too? If so, which one do I need to close to prevent it in the future?