Fresh Water Holding Tank - Do I need to keep water in it?

I full time and keep my fresh water tank full. But I also run the water off the fresh tank using the pump. This way I do not have to worry about a pressure regulator on the hose or high water pressure from the RV park. It's just me so I have to fill the tank about 3 times every 2 weeks. Plus you never know when there will be a problem with the park's water lines. I also have a power fill setting on my rig so it doesn't take long to fill the tank.