This project was started just after the roof ice ripped off the main water supply pipe.
Instead of replacing it and having the same problem again in a few years, I decided to take the water barrels off the roof and bring them inside and under the cabin.
Due to the lack of resources, I had to reuse all the existing parts. As I was fumbling around through the plumbing box of fittings, I figured I had enough stuff to upgrade the system and bring the water barrels under the cabin. One of the biggest advantages was running water could be utilized longer in the fall and cold months. When the barrels were on the roof, they were acceptable to cold nights where the temperature would drop down below freezing and pipes would crack.
I also had a decent RV water pump that could be plugged into the 1000 watt inverter on the battery bank. After 5 years, the system had finally come together.