This tool helps builders calculate the often-overlooked weight of the plumbing system. While PEX vs. Copper is a debate, the real weight killer is water itself. This tool calculates the massive weight penalty of towing with full tanks (Fresh/Grey/Black) and demonstrates why “Traveling Dry” is the golden rule for tiny houses.
Plumbing Weight Calculator
Calculate the weight of pipes, tanks, and water loads.
1. Piping Material
2. Holding Tanks (Gallons)
System Dry Weight
0 lbs
Pipes + Empty Tanks
Total Wet Weight
0 lbs
+0 lbs Water
H₂O
Heavy Load Warning: Towing with full tanks adds significant weight. Ensure your tank straps are rated for dynamic loads (G-forces).
PEX vs. Copper & The “Slosh” Factor
8.34 lbs per Gallon
Water is heavy. A standard 40-gallon fresh water tank adds 334 lbs. A 100ft run of 1/2″ pipe holds only ~1 gallon of water, so the pipe volume is negligible compared to the tanks.
Material Comparison
- Copper: ~0.30 lbs/ft (Heavy, prone to freeze burst)
- PEX: ~0.05 lbs/ft (Light, flexible, freeze resistant)
PEX saves ~25 lbs on an average tiny house vs copper, but saves hours in labor.