RV Water Heater Smells Like Rotten Eggs

The Short Answer: If the rotten-egg smell comes only from hot water at the faucets, it is usually hydrogen sulfide formed in the tank from sulfur in the water, often worse after storage. Suburban calls it unpleasant but not harmful and recommends chlorinating the water system and replacing the anode as needed. If you smell rotten eggs in the air, treat it as a possible propane leak first.

Air or water?

• Smell in the air around the bay, the access door, the regulator, or inside the coach: possible propane. Leave and get help first. Do not troubleshoot the water heater.
• Smell only from hot water, cold water fine: the water heater tank is producing it.
• Smell from hot and cold water: the fresh water tank, hose, or campground supply.
• Smell from drains or the bathroom: a dry trap or holding tank, not the water heater.

Why the tank makes the smell

Many water supplies contain sulfate. In a warm tank, bacteria and reactions with the anode rod can turn it into hydrogen sulfide gas. Water sitting in the tank for weeks makes it worse. Suburban’s manual (opens in a new tab) describes this as “sulphur water,” notes it is not harmful, and also recommends draining the tank whenever the RV is not in use.

Suburban steel tanks have an anode rod; Atwood/Dometic aluminum tanks do not, though they can still develop odor from stagnant or sulfur-rich water.

Suburban’s chlorination method

Suburban’s manual recommends chlorinating the water system:

1. Add about 6 ounces of regular household liquid bleach for every 10 gallons in the RV’s fresh water tank.
2. Run the chlorinated water through the system, opening each faucet one at a time until you smell chlorine.
3. Let the RV sit for a few days.
4. Flush the system with fresh water until the chlorine smell is gone; this may take several rounds.

If the smell continues, flush again and replace the anode rod as needed. Make sure the water heater is not in bypass during this, or the tank will not be treated. Turn off the water heater’s gas and electric switches before draining the tank, and only reheat once it is full again.

Preventing it

• Drain the water heater during storage. Suburban’s manual recommends removing the anode to drain its tanks.
• Replace a Suburban anode yearly, or sooner if it is heavily corroded.
• Keep RV antifreeze out of the water heater when winterizing; Suburban notes it is corrosive to the anode.
• Consider a water filter at the hose connection when campground water smells of sulfur.

Related: tankless water heater sulfur smell, RV water heater leaking from the bottom, and hot water heater smells fishy.

Frequently Asked Questions

Q: Should I switch to a different anode material? A: Use only anodes approved for your heater. Suburban warns against non-Suburban parts in the anode opening. If the smell keeps returning after chlorination and a new anode, ask the dealer whether an alternative Suburban anode suits your water.

Q: Is it safe to shower in water that smells like sulfur? A: Suburban describes sulfur water as unpleasant but not harmful. If the smell is in the air rather than the water, treat it as propane and leave first.