Our 2005 Jay Feather LGT 27P has a 36 gal fresh water tank. Experience has shown that a full tank will last us about 3 days of cooking, toilet use, washing dishes and hand washing. We use the campground facilities for showering. For longer stays at the camp grounds, I have a 60 gal plastic water tank I can throw in the back of the truck. I put water into the tank at the campground's drinking water fill station. When needed, I just run a water hose from the tank in the truck to the tank filler point on the trailer. Gravity does the rest, don't need a pump.
I also have a black/grey water portable tank (aka: turd toter) if I need to empty the grey tank.
FAA A&P mechanic, ex-RV dealer parts dept
Retired B-52 Gunner/Flight Examiner, B-52 Crew Chief
2016 Jayco Eagle HT 29.5 FBDS w/ 15,000 BTU AC, 50 amp service, upgraded counter top, thermal pane windows, elec. stab jacks, outside grill, backup camera and MORryde pin box.
2011 GMC 2500HD DURAMAX/ ALLISON