Re: water presure regulator
A water regulator goes into your water supply line, and prevents pressure in the RV from exceeding its set value. They are available in fixed and variable. Camping World has them or at least the fixed ones.
They are usually a brass tube about 4 inches long, with a male hose fitting on one end and a female hose fitting on the other.
They can go anywhere, from directly at the water source, somewhere in the middle of the hose, right at the entrance to the RV, or even built into the RV.
Fixed, at around 40 to 50 PSI, is fine for RV usage. I think many water sources are 80 PSI or more, and the hose can act as an 'amplifier', particulary if the sun shines on it.
Note that not using one of these will probably cause you problems. I didn't use one 'just for an hour' and blew the pressure sensor on my water pump and the supply line to the toilet.