Have both 12V and 120VAC at the base of the rear awning hinge. Wifey can do any kind of awning lights and I can reach all the tires with a 12V air compressor.
Actually it is a 120v heated water hose, I have not seen any 12v water supply hoses. I got mine at a farm supply store or Amazon. I would place a 120v outlet on street side in case there is no 120v near the water source
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Jim
Sometime life gets in the way of living.......
I'd not get a 12V outlet for a water hose heater. How many times do you have city water but not a 120V source?
You could put a 120V outlet near the hose inlet. But I'd opt for an extension cord for the water hose heater rather than putting another hole in the shell.
As mentioned there are a lot of other reasons for a 12V outlet, but I'd forgo one for a water hose heater.