RV Water Heater Leaking Outside the Coach
On this page (5 sections)
The Short Answer: Water on the ground outside an RV, below the water heater’s access door, most often comes from the pressure-and-temperature relief valve doing its job as the tank heats. Next most common are the drain plug or anode, a fitting behind the heater, and, on older heaters, the tank itself. Dry everything, watch which part gets wet first, and treat a wet tank shell as a replacement.
The relief valve is the usual source
Look for a brass valve with a lever near the top of the tank, visible through the outside door. Suburban’s manual explains that an RV water system is a closed system, so when the water heats and expands, pressure rises until the relief valve opens at 150 psi (or at 210°F) and drips. It calls this normal and says it does not mean the valve is defective. The drip falls straight down onto the ground or the RV’s frame, which is why it looks like a leak.
Suburban suggests maintaining an air pocket at the top of the tank to reduce how often this happens; see RV relief valve dripping for that procedure and for causes that are not normal, such as very high campground pressure.
Never plug or cap the relief valve.
Other sources, by location
| Where it is wet | Likely source | What it usually takes |
|---|---|---|
| Valve near the top, wet only while heating | Relief valve releasing expansion | Air pocket, pressure regulator; valve only if it drips constantly |
| Large plug at the bottom of the tank | Drain plug (Atwood/Dometic) or anode rod that doubles as the drain (Suburban) | New plug, anode, or seal |
| Behind the access panel, from the coach side | Inlet, outlet, or bypass valve fittings | Fitting repair from inside the coach |
| Electric element cover on dual-fuel models | Element gasket | Gasket or element, done with power off |
| Rust streaks or wetness from the tank jacket with fittings dry | Tank shell | Replace the heater |
| Only after rain or washing the RV | Water entering around the door or frame | Seal the exterior, not the heater |
How to find it
- Turn off the water heater’s gas and electric switches, the water pump, and city water.
- Let the tank cool so any hot water at the relief valve is not a burn risk.
- Dry the tank face, plugs, and fittings with paper towels.
- Restore water pressure (without heating), wait, and check each spot. Then heat the tank and check again.
Water that appears only while heating is almost always the relief valve. Water that appears as soon as the system is pressurized points to a plug, fitting, or the tank.
Repairs and replacement
A drain plug or anode is a routine replacement once the tank is cool and drained; use the part that matches your heater. Suburban’s manual warns against replacing the anode with non-Suburban accessories such as add-on heating elements. Do not over-tighten a plastic plug into an aluminum Atwood/Dometic tank.
A leaking tank cannot be repaired. Sealants and patch kits on a pressurized tank are not safe. If water is reaching the burner or electric controls, leave both switches off until the heater is inspected or replaced.
Related: RV water heater leaking from the bottom, Suburban RV water heater leaking, and RV water heater troubleshooting.
Frequently Asked Questions
Q: Is it safe to keep using the water heater while it drips from the relief valve? A: If the drip is occasional and only during heating, Suburban describes that as normal. A steady stream, or dripping when the tank is cold, needs attention before further use.
Q: Why does my RV leak outside only when connected to city water? A: Campground water pressure can be high. Without a pressure regulator on the hose, that pressure pushes the relief valve and fittings harder. A regulator at the hose connection is standard RV practice.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Suburban: SW10D/SW10DE/SW10DM/SW10DEM installation and operation manual (copy hosted by Forest River) (opens in a new tab)Suburban SW10 models: relief valve behavior and anode/drain arrangement; other Suburban SW models are similar, Atwood/Dometic tanks differ.
- Suburban: service and support (opens in a new tab)Identify the appliance behind the RV badge and obtain its operating instructions.
- Dometic: product support (opens in a new tab)Product manuals and support for Dometic equipment; confirm coverage of any legacy Atwood model.
- A. O. Smith technical bulletin 51: puddles around a heater (opens in a new tab)Common water-leak sources and the distinction between fittings and a failed tank.
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