RV Water Heater

An RV water heater is an onboard water heater that runs on propane, electric, or both. Typical tank capacity is 6 to 10 gallons; some modern rigs have tankless on-demand water heaters.

Two types

Tank-style water heaters (most common)

Atwood and Suburban brands dominate. Tank capacity:

• 6 gallon — most common in Class C and travel trailers
• 10 gallon — some Class A and larger trailers

A 6-gallon tank provides about 8-10 minutes of typical shower use before running cold.

Tankless on-demand water heaters

Newer luxury rigs use Truma AquaGo or similar tankless heaters. Endless hot water as long as fuel and water flow continue. More expensive to install; standard in some premium Class B builds.

How to operate

For tank-style:

1. Turn the heater on (button on the control panel or a switch labeled “WH”)
2. Choose fuel source — gas (propane) or electric (shore power only)
3. Wait 15-20 minutes for the tank to heat
4. Use hot water at any tap or in the shower

For tankless:

1. Open a hot water tap — the heater fires automatically

What “electric only” means

Most tank-style water heaters can run on:

• Propane only — works any time
• Electric only — requires shore power (the heating element draws ~1,200W)
• Both simultaneously — fastest heat-up, called “DSI” or dual-source

For boondocking trips, use propane mode. For full hookup trips, electric saves propane.

Common rental issues

• Pilot light won’t ignite — common at altitude; use the DSI electric start mode
• Element failed — water only heats on propane, not electric
• No hot water at all — bypass valve might be in winterized position; check the bypass valves under the bathroom sink
• Cold water comes out hot tap — opposite plumbing somewhere; ask the rental company

Conservation tips

• Navy showers — wet, soap, rinse, off. A 6-gallon tank can handle 3-4 of these.
• Turn off the water heater when not needed (boondocking)
• Use cold water for hand washing — saves the heater for showers