How to Set Up and Use Your RV’s Fresh Water System

Your RV can supply water from its onboard fresh water tank using the water pump or directly from a pressurized city water connection. Before using either source, sanitize the system as directed, close the drains, and confirm the valves are positioned correctly. Use only potable water and a hose intended for drinking water.

What equipment do you need?

• Potable water hose: Use a dedicated drinking-water hose for filling the tank or connecting to city water.
• Water pressure regulator: Use a regulator to control incoming pressure when connecting to a pressurized supply.

Keep your drinking-water hose separate from hoses used for wastewater-related tasks.

What should you check before adding water?

Locate the fresh water tank drain and the hot- and cold-water low-point drains, usually underneath the RV. The tank drain empties the tank, while the low-point drains help empty the plumbing lines.

Drain locations, colors, and valve arrangements vary by model. Confirm that the appropriate caps and valves are closed before filling or pressurizing the system.

Sanitize the fresh water system before first use and at the intervals specified in your maintenance instructions. Follow the prescribed sanitizing procedure, including dilution, contact time, and flushing.

How do you fill the fresh water tank?

Use the onboard tank when camping without a direct water connection. Water weighs approximately 8.3 pounds per gallon, so account for it when loading your RV and checking weight limits.

Your RV may have a gravity-fill opening or a pressure-fill arrangement.

Gravity fill

1. Remove the cap from the opening labeled for fresh water tank filling.
2. Insert your potable water hose and turn on the supply.
3. Stay with the RV and monitor the fill level.
4. Turn off the water when the tank is full, remove the hose, and replace the cap.

Pressure fill

1. Connect your potable water hose and regulator to the designated inlet.
2. Set the convenience-center valves to the tank-fill position shown on your RV’s instructions.
3. Turn on the supply and monitor the tank level.
4. Shut off the supply when full and return the valves to the appropriate operating position.

Never leave the RV unattended while filling or allow the tank to overfill. The tank-fill system does not provide an automatic shutoff. 

How do you use water from the onboard tank?

With water in the tank and the valves correctly positioned, turn on the water pump switch, usually found on the monitor panel.

Open a faucet to release air and establish water flow. The demand pump runs as needed to supply water and should stop after the faucet closes and the system reaches pressure.

If the pump continues running with all fixtures closed, investigate before leaving it operating.

How do you connect your RV to city water?

City water supplies pressurized water directly to the plumbing. It normally does not fill the fresh water tank unless your RV’s valves are set for tank filling.

1. Leave the water pump off for normal city-water use.
2. Connect a potable water hose and pressure regulator to the city water inlet.
3. Confirm the valves are set for city-water operation.
4. Turn on the supply, open a faucet to purge air, and inspect accessible connections for leaks.

Avoid leaving the RV connected to an active water supply unattended for extended periods.

How do you fill a tank-style water heater?

Keep both gas and electric heating modes off until the water heater tank is full.

1. Confirm the drain plug is installed and the bypass valves are in the normal-use position.
2. Supply water through the pump or city water connection.
3. Open a hot-water faucet to let air escape.
4. Once water flows steadily without sputtering, close the faucet and check for leaks.

Use the hot-water faucet to purge air rather than opening the exterior pressure-relief valve as a routine filling step. For a tankless heater, follow its specific startup instructions. Keystone RV

Check your Owner’s Manual for the valve layout and setup instructions specific to your RV.