Water heater help

[Rwalsh79]

Hi i just bought a 2012 swift 154bh. It was not properly winterized and the hot water heater was broken when i got it. I do plan on eventually replacing it, but was told by the previous owner that the toilet and the sink cannot be used without the hot water heater. Is this true? I did try to google but got a mixed bag of info. Thanks and we are really enjoying our new jayco!

[WinnieView]

There may be a bypass valve near the HWH that when closed will still allow water to flow throughout the RV.