Water heater

When the hot water smells

RV water heaters (Suburban, Atwood/Dometic, and similar) hold a small tank of water, a sacrificial anode, and often both LP and electric heat. The classic complaint is rotten-egg hot water. That is usually the tank, not the black tank.

Rotten-egg hot water

Sulfur bacteria in a still tank make hydrogen sulfide. You smell it at the faucet when you run hot — cold is fine. A magnesium anode can feed that reaction. Many owners switch to an aluminum anode, flush the tank, and sanitize the fresh-water system.

Don’t confuse this with a propane leak. Propane smell is in the air. This smell is in the water.

LP exhaust and burnt-dust electric

A gas water heater vents out the side. If that cap is blocked by a storage bin, mud dauber nest, or a parked wall, exhaust can wash back along the coach. An electric element that ran dry can smell like hot metal or burnt dust until you replace it.

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Smell is in the hot water, not the whole cabin. Cold water is fine. Ruled out a propane leak in the air. This is water, not gas. Water-heater tank drained and flushed (bypass valves, anode plug, lots of water). Anode rod inspected. Replace if it’s a stub; consider aluminum if magnesium + sulfur water is the pattern. Fresh tank and lines sanitized if the whole system sat. Exterior exhaust/intake cap is clear of nests, tape, and storage gear. If it ran on electric with a dry tank, the element may be cooked — smell of hot metal, no hot water.