Most RVs are equipped with an on-demand water pump.

The water pump is the heart of your freshwater system. It pressurizes the water from your fresh water tank for delivery to your sinks, showerheads, and toilets.

An RV water pump is powered by 12V electricity from your battery. When you open a faucet or flush a toilet, the pump detects a drop in pressure. It will cycle on and pump water through the supply lines until the flow is cut off and the pressure rises.