Hello Pop-up Portal- We just bought our first pop-up trailer, a new-to-us 2006 Jayco Series J 1007 model. We've had it popped up in the driveway for the last few weeks trying to sanitize and get all of the kinks worked out on weekends (and making sure it can stand the weather) before taking it on our first voyage later this week. My problem is that the water lines won't pressurize on either city water or pumping out of the fresh water tank. I've watched many videos, searched through many forum threads, and have tried many things (learning much in the process), but I'm still stuck with a water system that will not pressurize and actually work. Background: the former owner (owned it for just a few years) said they never used the water system when camping, but it's visibly apparent that quite a few aftermarket upgrades have been done to the camper, separate from the plumbing. The water lines appear to be in almost new condition and no visible leaks anywhere and I wouldn't be surprised if this system was restored prior to the former owner purchasing. The system: two water outlets--the sink and an outdoor shower. It has a 17-gallon fresh water tank, and a 6-gallon water heater (Atwood brand). Current status: I have filled both the fresh water and water heater tanks. I've checked all relevant valves in the system (supply from fresh water tank is open; low-point drain valves are closed). No apparent kinks in lines anywhere. When I try running from fresh water tank: I turn on the pump, it is audibly running and appears to be working as well -- for example, I used the diverter valve to pump a little bleach into the system, and this did work (albeit somewhat weak--it didn't suck on a second attempt to add more bleach in). So it's probably (?) not a bad pump. Yet, the pump will run for many minutes with the sink faucet open and nothing ever comes out. When I try running from city water: Again, leaving sink faucet open, nothing comes out even after 20 minutes of letting the water run (and nothing is visibly coming out of the system from under the carriage). I'm genuinely stumped, any thoughts or ideas welcome. Thank you!