An RV fresh water tank is a tank that carries clean water for your use in your RV. This tank is connected to a pump that then brings your clean water to your toilet, tub or shower, and sinks of your RV. When a city water hook-up is available, you can by-pass the use of your stored clean water and pump city treated water into the RV's plumbing valves instead. The whole system works and also looks much like the plumbing of your home. Some RV owners always choose to fill and use their fresh water tanks for their plumbing needs, even when city water is available. This is a matter of preference.
