Could RV Smell Like Propane from the Hot Water Heater?

The smell of propane in an RV’s hot water heater can be a cause for concern, and it is important to determine the source of the smell to ensure safety. While propane itself is odorless, an additive is used to give it a distinct smell, which can be mistaken for exhaust fumes. The smell of exhaust fumes can be a sign of a leak in the exhaust system or a blockage in the venting system, which can cause a backup of fumes into the living space.

Identifying the Source of the Smell

To determine if the smell is propane or exhaust fumes, it is recommended to perform a soap bubble test on all propane connections, including those under the RV. This involves turning on the propane and squirting soapy water on the connections to look for bubbles, which would indicate a leak. The soap solution should be a mixture of 1 part dish soap to 3 parts water, and the test should be conducted with a spray bottle or a small brush.

If the smell is coming from the exhaust fumes, it is important to inspect the exhaust system for leaks or blockages. This can be done by visually inspecting the exhaust pipe for any cracks, holes, or loose connections, and by checking for any obstructions in the vent, such as debris or bird nests.

Understanding the Water Heater Venting System

could rv smell like propane from the hot water heater

If the water heater is not a direct vent with PVC or a metal flue into a chimney, it is possible that the flue fitting is not sealed and relies on hot air rising to create a draft. This type of water heater is known as a “gravity-fed” or “atmospheric” water heater, and it requires a proper draft to function correctly.

Any type of blockage in the vent can cause fumes to back up or not be carried outside completely. This can happen due to a variety of reasons, such as a bird’s nest, debris buildup, or a damaged or disconnected vent pipe. It is important to ensure that the water heater has plenty of fresh air to allow for proper exhaust.

Ensuring Proper Ventilation

To ensure proper ventilation for the water heater, it is important to check the following:

  1. Vent Pipe Condition: Inspect the vent pipe for any cracks, holes, or loose connections, and replace it if necessary. The vent pipe should be made of a non-combustible material, such as galvanized steel or aluminum, and should be properly sealed at all joints.

  2. Vent Pipe Size: The vent pipe should be the correct size for the water heater, as specified by the manufacturer. Typically, a 3-inch or 4-inch vent pipe is used for a standard RV water heater.

  3. Vent Pipe Length: The vent pipe should be as short and straight as possible, with a minimum number of elbows or bends. The total length of the vent pipe should not exceed the manufacturer’s recommendations, which is typically around 15 feet.

  4. Vent Pipe Termination: The vent pipe should terminate outside the RV, with a proper termination cap or vent hood to prevent the entry of rain, snow, or other debris.

  5. Fresh Air Intake: The water heater should have a dedicated fresh air intake, which should be located away from any potential sources of contamination, such as the vehicle’s exhaust or the RV’s entry door.

By following these guidelines and addressing any issues with the water heater’s venting system, you can help ensure that the RV’s hot water heater is operating safely and efficiently, and that any propane or exhaust fumes are properly vented to the outside.


In summary, the smell of propane or exhaust fumes in an RV’s hot water heater can be a sign of a leak or blockage in the system. Performing a soap bubble test on all propane connections and inspecting the exhaust system can help determine the source of the smell. It is important to ensure that the water heater has plenty of fresh air and that any leaks or blockages are addressed promptly to ensure safety.