Actually lots of good info and I'm never too worried about getting too much!
So some thoughts that show up!
One of the problems with water and leaks is that it is hard to tell old water marks from new ones if we can't actually feel the spot!
But for info? The pump and that area looks good, no signs of water but some info on what and how it works may help for later. For the age, etc. it looks pretty good!
Good stuff to know! Water normally comes from the tank, through the filter and pump when the valve handle is aligned with that tubing! Then it goes to a tee and splits to other parts of the RV like blue line. Then when wanting to fill lines with antifreeze, turn the handle up to align with the suction tube I marked in green.
I think that is a plastic cap to remove and then stick the tube down in a jug of antifreeze. That lets antifreeze be sucked in when you turn the pump on and go to each faucet, stool, etc. that uses water. I tend to go to the one closer to the pump and open it until I see the pink antifreeze come through, then close that and go to the next. Each time, I also let some pink (half cup?) run down into the trap where there should be water standing as a way to protect that water from freeze.
The label is a good place to find what to replace the pump if ever needed!
Shurflow brand is common but there are different models!
A test to see it actually is going to suck is to stick your finger over the tube end and feel it sucks when pump is on! See that crimp in the tube where it comes off the pump? That "might" be enough to stop flow and you may want to cut that part off and reattach to avoid crimping or maybe it is no problem if you are aware and find the pump doesn't suck your finger! Maybe a popcycle stick taped to keep it straight until redone?
Hint to avoid future when reopening RV? When done sucking anti in, turn the knob and put the stopper back or you are likely to have trouble getting water right when you reopen. Harder to figure out if we wait three months so I do it NOW!
Don't forget to do the stool valve and fitting for that line!
This area looks good with no leaks but they have left a couple items to roll around and make noise?
Not totally sure of the next picture other than they are drains for each line.
I think you are meant to pull up or twist that ring to open a line that goes down through to under the RV! Rings are flimsy handles but they may also indicate which way the valve is set and show water flows past here instead of draining! I think simply turning is all that is needed???
They look like they are sealed down to the floor but I think there will be tube going straight down and out. this lets water out before winter but needs to be closed when adding antifreeze or it also goes on the ground!
Open to drain then close to use antifreeze!
On to the ugly at the heater!
Lots of signs it has leaked now or other times is the big question! Signs like feeling it wet are more sure! I think there has been work here before and some has been changed. Some of the white stuff that looks like spray paint is something added that I don't know about but looks like somebody has been here before?
This lets you decide if water goes in the heater or bypasses. It is somewhat standard to let the handle show which way the water flow. Not always but kinda/sorta standard!
Is that darker stain to the right of where the cold goes into the bottom showing it is new and not totally dried yet or just different because it has been soaked more often?
This looked like a real suspect to turn a little water on to look for a spray where the dark stain or other points.
I think I see a check valve as a white item where the hot would come out of the tank? A check valve is a one way thing that should only let water come out. That stops hot water from coming out of the heater, cooling and then going back in to make the heater work more! If you have the heater running and don't get hot water, this valve can stick closed and stop water flow. Not a big frequent thing but happens?
I might also see a white mineral deposit on the fitting just behind the bypass valve? That looks like an oozing leak has been dripping there for quite a while ---or maybe now?
Cleaning the minerals off and retighten that fitting might be a good plan for maybe someday? As a way to avoid trouble, it may be that the handle for the cutoff is stiff and turning it puts stress on that fitting. Maybe check for crack at that point? Try to avoid turning the whole thing when moving the handle? People and plastic can work the same as they get older. Give them a bit more gentle care!
Last item I see is a guess! I may see two black rubber hoses at the bottom. That makes me think of radiator hoses that bring water from the engine radiator back and pass it through near the fresh water tank. This is a feature that some have It adds to cooling the engine but also lets some heater transfer to the fresh water heater. Saves some propane but you can also fin it nice to arrive after a long drive and already have hot water.
IF that is what you have, it is called "motoraid" and may be an added options/feature! I like them but they are pretty scarce on newer RV!
Maybe feel these hoses after motor gets warm to see if they are heater hoses?
Usually we want to turn the pump on only when we have no pressure water from the hose. It isn't a crisis to have both on except it tends to make the pump work when not needed. I tend to only turn it on as I need water when not connected and then turn it off as a way to avoid floods or running down batteries if something fails.
But one bigger reason is the nasty habit they have of coming on in the middle of the night if the pressure creeps down while I am sleeping. It tends to scare me to death!
There is a pressure setting gizmo at the end of the pump but things are rarely 100% dependable!
Whew! I stop now for our brains to rest!