The city water connection is attached to the fresh water system via a solid PEX connection. Every trailer might be different depending on how careful the installer was with using the correct length of PEX, but this tends to put stress on the Shur-Flo inlet/pressure reducer assembly, pulling down or pushing up on the back of the assembly...I've had three of them crack, and when they do, they leak, either inside down the wall, or in between the inner and outer skins, soaking the insulation, and in my case, the subfloor as well. Most recently, I kept hearing my pump cycle (using fresh tank) every couple hours, just for a second or two...so I knew there was a leak somewhere. Even if not using a city water hookup, there is pressure against the valve assembly from the water pump pressure, so if it's damaged it will leak.
On my trailer (23d/corner bed) the City inlet comes in under the bathroom sink. I felt around back there and noted that the insulation under the inlet, and the insulation I could feel through the hole for the black tank flush connection, was soaked, and the floor was wet and stained at the bottom.
Rather than just replace the Shur Flo assembly (Again) I decide to take some torque off the assembly using a flexible hose, and hopefully avoid the cracking issue. At the same time, I added a valve that allows me to actually isolate the assembly from the fresh water system to keep it from freezing if using the trailer (via the fresh water tank, not city water) in winter temps. And also isolate the inlet assembly if it starts to leak again while on the road, to avoid water leakage while on the road and waiting to replace it.
Here's what I got:
New city water inlet assembly. $35 at various places:
Braided water line with quarter-turn shutoff valve on one end (Sharkbite connection was my choice given the tight space to work in). $14 at Home Depot.
First, I turned off the water pump and drained the cold water low point drain, then removed the old city water inlet on the outside via the four screws, then and unscrewed it from the interior PEX line.
Next, I attached the new hose/shutoff valve assembly to the new city water inlet.
I then fed the shutoff valve end of the new hose in to the trailer, and reinstalled the screws to secure the new city water inlet assembly. I reused the old screws, and also the new inlet did NOT have a gasket in the box, so I carefully peeled the existing gasket from the old assembly. Your mileage may vary, I think they generally include a new gasket but mine never made it in to the box.
Now, back in to the trailer. I identified a place to cut the PEX pipe that leads up to the city connection, that would be easy to install the new connection, allow access to the valve I added, and also provide plenty of slack to take tension off the back of the city connection assembly. I then cut the pipe at that point using a PEX cutter, removed the piece of pipe with the old connector on the and, and attached the Sharkbite valve fitting where the pipe was cut.
Job done! There is now no tension pulling on the plastic inlet assembly. As an upgrade, I have the option (I like options) of being able to drain the assembly via a low point drain, and then shut off the valve. Then when pressurized with the pump, water will not travel up the new braided hose and in to the inlet assembly, minimizing the chance of freezing if camping in cold weather and using the fresh tank rather than a water hookup...which is my preference to avoid heating water hoses and all that. It also gives me the ability to shut off water pressure into the back of the city inlet fitting when using the water tank and pump, in case the inlet cracks again, allowing leaks down between the skins. I can effectively remove the city inlet fitting from the system.
I think this is a worthwhile mod mainly to use a flexible hose to remove the tension from the PEX from the back of the Shur Flo inlet assembly; the shutoff valve is obviously not needed but simply provides some flexibility to control what's going on. Sorry for the sideways pics.