How to Replace an RV Water Heater | A Step-by-Step Guide for DIY Repair

Replacing an RV water heater can be a real pain, but I’m here to walk you through it step-by-step. I know it seems daunting, but have no fear – you totally got this! Just get your tools and materials together and we’ll go through it real easy-like. Safety first though – we gotta turn off the power and water so there’s no surprises. I’ll be with you the whole way, from draining the old one to testing the new heater. With a little time and patience, we’ll have your RV hooked up again before you know it. So let’s get started and get your hot water flowin’! It’ll be a piece of cake, I promise. Just stick with me and we’ll knock this project out, no problem.

How to Replace an RV Water Heater

Step 1. Gather the Necessary Tools and Materials

Replacing an RV water heater requires gathering a few key tools and materials ahead of time. Having these ready will make the process smoother. 

Tools Required:

  • Screwdrivers – Have both Phillips and flat head screwdrivers on hand.
  • Adjustable wrench – Helpful for loosening fittings and connections. Avoid over-tightening.
  • Pipe wrench – Provides extra grip and torque for stubborn connections.
  • Teflon tape – Used to seal threaded pipe connections.
  • Pipe cutter – For cutting water lines to size if needed.
  • Plumber’s tape – To wrap pipe threads and prevent leaking.
  • Voltage tester – For testing electrical connections safely.

Materials Needed:

  • New RV water heater – Choose a unit with similar dimensions and connections as the old one.
  • Replacement fittings – For any damaged or corroded fittings that need replacing.
  • Pipe insulation – To insulate any exposed portions of the new water lines.
  • Pipe sealant – Used on fittings to prevent leaks. Look for RV-specific sealant.

Having all the necessary tools and materials will prevent delays in the project. Check that everything works beforehand.

Step 2. Turn Off the Power and Water Supply

Before draining and removing the old RV water heater, the power and water supply must be turned off. This is an essential safety step. You’ll need to locate the circuit breaker for the water heater and switch it to OFF

For propane units, turn the propane supply valve to OFF

For electric models, unplug from any outlet. Then find the main water supply valve, usually near the water hookup inlet on the RV exterior. Turn the valve clockwise to OFF to shut off water to the entire RV. With power and water supply halted, the old unit can now be drained and disconnected safely.

Step 3. Drain the Old Water Heater

Before removing the old RV water heater, its tank must be fully drained to prevent any remaining hot water from spilling out. You’ll need to locate the drain valve at the bottom of the tank and attach a hose to the valve spout so hot water can drain safely away. Find and open the pressure relief valve on the tank to allow air in so water can drain out. Place a bucket under to catch any released water. Turn the drain valve to OPEN and allow all water to fully drain. Once empty and only air comes out, close the drain. The old unit is now ready for disconnection and removal.

Step 4. Disconnect the Old Water Heater

Before unbolting the old heater, its gas, water, and electrical lines must be disconnected. You’ll need to turn OFF the gas supply at the propane tank or natural gas hookup, then loosen and disconnect the gas line with a pipe wrench. Cap the open line to prevent leaking. Loosen the cold inlet and hot outlet water lines with pliers or a wrench and cap the open ends. Unscrew the electrical cover plate and detach the wires, labeling them for proper reconnection later. The old unit is now ready to come out.

Step 5. Remove the Old Water Heater

With all connections detached, unbolt and remove the water heater from the RV. Locate the mounting bracket bolting it in place and unscrew each bolt while supporting the weight. Slowly pull out the old heater, taking care not to spill any water remaining inside or damage surrounding structures. Carry the empty old heater out and set it aside.

Step 6. Prepare the New Water Heater

While the space is clear, inspect the new replacement unit thoroughly for any defects and verify it matches the RV model. Install any necessary adapters, valves, or fittings according to manufacturer instructions. Refer to the old heater setup if needed. Wrap all threaded pipe connections with 2-3 layers of Teflon tape to prevent leaks when installing. The new water heater is now prepped and ready for installation.

Step 7. Install the New Water Heater

With the old unit out and the new one prepped, it’s time to securely install the replacement. Carefully lift the new heater into place under the mounting location, aligning it with screw holes. Insert mounting bolts through the holes and tighten them securely with a wrench. Reconnect the cold and hot water lines to the proper fittings, using sealant and tightening with a wrench. Reconnect the gas line and check for leaks after turning on the supply. Attach electrical wires per the wiring diagram and secure the cover plate. The hard work is done!

Step 8. Test the New Water Heater

With secure connections, turn on water and power to test the replacement. Locate the main valve and turn it to OPEN, checking fittings for leaks and tightening if needed. Restore electrical power and propane supply. With pressurized water flowing, inspect thoroughly for leaks and fix any immediately. Run a hot tap to prime the new tank and ensure the temperature reaches around 120°F.

Step 9. Insulate Pipes and Clean Up

With the new heater working, wrap any exposed pipes nearby with insulation to prevent heat loss. Use foil wrap or tape to secure the insulation tightly. Discard any debris, wipe up spills, and restore any displaced interior surfaces.

Step 10. Final Checks and Troubleshooting

Do one final inspection of all connections for tightness and leaks. Retest hot water temperature at all faucets. If any issues arise such as no hot water, check the power supply and gas valve position first. For leaks, tighten fittings and check for cracks. Refer to the user manual for other troubleshooting tips.


Replacing an aged or faulty RV water heater is a major project, but this step-by-step guide has equipped you to DIY the repair and save hundreds in labor costs. Gather the right tools and materials, follow safety procedures, and take your time. While hiring a professional is an option, have confidence you can get your RV’s hot water working again by meticulously installing a new heater. Here’s to many more safe and comfortable RV adventures ahead!

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