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What to Do If Your RV’s Fresh Water Smells Like Rotten Eggs

What to Do If Your RV’s Fresh Water Smells Like Rotten Eggs

If your RV fresh water smells like rotten eggs, this post has the troubleshooter for you. There are several reasons why a rotten egg smell may come from the tap in your RV, and in most cases, the issue isn’t difficult to resolve. But narrowing down the culprit is key.

In this post, we’ll tell you exactly how to determine why your RV water smells like rotten eggs and what you can do to resolve the issue.

What to Do If Your RV Fresh Water Smells Like Rotten Eggs

That “rotten egg” smell is hydrogen sulfide. To determine why an RV’s water is giving off the smell of rotten eggs, you’ll need to investigate by asking and answering a few questions.

The first step in troubleshooting the issue is to determine where the odor is coming from. Begin your investigation by checking to see if the smell is coming only from the hot side or from both the hot and cold sides. Note that the rotten egg/hydrogen sulfide smell rarely comes from only the cold side.

Smell Comes From Hot Water Side Only

Turn on the faucet to run only the hot water. If there’s no rotten egg smell, move on to Step 2. If, however, you notice that the rotten egg smell is coming from only the hot side, the source is likely your water heater.

What to Do If the Rotten Egg Smell Comes From the Hot Water Side

If you saw our post on RV water heater anodes, you know that some RV water heaters (but not all) have either a magnesium or aluminum anode rod. Generally, only Suburban brand water heaters require an anode rod, which is installed to protect the steel tank from corrosion. Atwood brand water heaters generally don’t use anodes because their tanks are made of aluminum. And RV tankless water heaters don’t have tanks at all, so they don’t need anode rods either.

If the source of the rotten egg smell is your water heater, you probably have a Suburban water heater with a magnesium anode rod installed (it’s the standard one installed by the factory and the most common replacement you’ll find online and in retail stores). Most likely, some anaerobic bacteria have gotten into the tank and are reacting with the magnesium in the anode rod, creating hydrogen sulfide gas (aka that “rotten egg smell”… anaerobic bacteria grow and reproduce without oxygen present, so an RV’s freshwater tank is a potential culprit for that reason).

If you determine that your water heater is the source of the odor, you’ll want to drain and flush it and replace the standard magnesium anode rod with an aluminum (or aluminum/zinc) rod, like this one:

SUBURBAN MFG Suburban 233516 Aluminum Anode Rod for Water Heaters
  • USE: Aluminum anode with commercial grade stainless steel core helps extend the working life of the anode rod and your hot water tank
  • DIMENSIONS: Best suited for high pH and soft water; 12"W x 5"H

Taking these actions should stop the rotten egg smell.

Here’s our video on how to drain and flush your water heater and replace the anode rod:

Smell Comes From Hot & Cold Water Running Together

Now that you’ve eliminated the water heater as the culprit, run the hot and cold water together. If you smell the odor of rotten eggs coming from both sides of your water system, your problem is likely related to one of two culprits: your fresh water tank itself, or the groundwater/city water system to which your RV is connected.

What to Do If the Rotten Egg Smell Comes From the Hot & Cold Sides Running Together

The remedy for the rotten egg smell coming from both the hot and cold sides of your water system will depend on where that fresh water is coming from (and what it’s coming through):

City Water/Groundwater

With your RV connected to the city water supply, let your hot and cold water run for a while. Does the smell dissipate as you run the water? If you notice that letting the water run reduces the odor, then the source is likely the groundwater or city water to which your RV is connected.

A city water spigot at a campground/RV park

Disconnecting from the city water/groundwater source will help to determine the cause of the rotten egg odor coming from your RV’s water system.

If the smell is coming from the city water source, notify the person in charge of your campsite. You may want to ask to move to a different site. If this is your permanent location for the RV, then you’ll likely need a water treatment specialist to put together the right incoming treatment solution to remove the smell from the incoming water.

Inline Filter or Water Softener

If you disconnect your RV from city water and then smell the water running from the spigot and there is NO smell, but there’s still a smell of rotten eggs coming into your RV when you reconnect to the city water source, do you have any inline (including whole house) filter cartridges or water softener canisters that could be contaminated?

Try running your water without the softener or filter inline to see if the odor is eliminated. If so, thoroughly clean out (or replace) the filter(s) and water softener canister to eliminate the source of the odor.

Your RV Fresh Water Tank

If your rig is NOT connected to a city water source (i.e. you’re running off your onboard water tank), and you’ve eliminated the possibility of an inline filter or water softener, but you continue to smell the odor as you run the hot & cold water in your RV, then your problem is in your RV’s fresh water tank itself.

If your RV’s fresh water tank smells like rotten eggs, you will likely need to drain and sanitize it (and your whole fresh water plumbing system) to remove the source of the odor.

You can use plain, unscented, liquid bleach as we do in our post on how to sanitize your RV water system. It’s best not to use the gel formula which has extra chemicals/components that can be harder to flush out of the plumbing system. You want regular liquid bleach:

Clorox Disinfecting Bleach, Regular - 64 Ounce Bottle
  • POWERFUL CLEANER: Keeps clothes whiter longer, disinfects 99.9% of germs (including norovirus, flu virus, MRSA, E. Coli, and Salmonella), plus, cleans...
  • DEODORIZER: Eliminate odor causing bacteria and help prevent the build-up of odors in your high efficiency and standard laundry machine with Clorox...

If you prefer, you can also use a dedicated freshwater system cleaner to thoroughly clean out the tank and plumbing system, like these:

Camco TastePURE Spring Fresh Water System Cleaner and Deodorizer for RV and Marine | Cleans and Freshens Water Lines | Great for Dewinterizing - 1 Gallon (40207) , 128 Fl Oz (Pack of 1)
  • Requires no measuring, mixing, or preparation
  • Stops bad odors and foul tastes in your drinking water by cleaning and deodorizing
STAR BRITE Aqua Water Shock for Boats & RVs - Instant Odor & Bad Taste Remover for Potable Water, 16 Ounce (097116)
  • INSTANT ODOR & OFF TASTE REMOVAL - Targets and neutralizes bad tastes and smells in your RV or boat's water supply, making every sip refreshing
  • SEASONAL STORAGE SOLUTION - Revives your water system after periods of inactivity, ensuring a fresh start to every adventure

Note: to avoid the use of bleach, some people use hydrogen peroxide to sanitize their RV’s fresh water tanks. If you plan to do this, be sure that you buy a high enough concentration of hydrogen peroxide so that, when it’s diluted, it will still provide enough sanitizing power (3% is required). Since typical hydrogen peroxide that’s available over-the-counter in retail stores is only a 3% solution, you’d need to buy enough of it to fill the tank!

Again, we prefer to use regular liquid bleach. The process is simple and effective. You’ll want to start with your fresh water tank somewhere between about 1/4 and 3/4 full, leaving room to fill the tank after adding the bleach,. Use 1/4 cup of bleach for every 15 gallons of fresh water tank capacity.

You can follow along with our step-by-step guide in our post on how to sanitize your RV water system.

How to Prevent Your RV Fresh Water Tank From Smelling Like Rotten Eggs

Be aware that not every RVer will encounter the smell of rotten eggs coming from their water. We’ve never experienced this situation in over 20 years of full-time RVing for a couple of reasons:

No Stagnant Water In Fresh Water Tank for Long Periods

Because we were full-timers, water never sat in our system unused for very long. Having the contents of our fresh water tank used and replaced on a regular basis helped to keep “stuff” from growing in there. When we were parked for an extended stay, we would either drain the tank completely, or use up (and refill) it every month or two.

Regular Cleaning of Fresh Water System

We’ve always made sure that our freshwater system, including the water heater, is thoroughly cleaned and sanitized at least once a year (or even every six months).

By staying on top of both of these two items, we eliminated the possibility of our RV’s fresh water tank from developing the anaerobic bacteria that can cause that nasty rotten egg odor. 🤢

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John S.

Sunday 14th of April 2024

Good post.

This was another 'learn something new every day" moment:

" It’s best not to use the gel formula which has extra chemicals/components that can be harder to flush out of the plumbing system. You want regular liquid bleach".

I've never seen or used gel bleach, but that's good to know.

TheRVgeeks

Monday 15th of April 2024

LOL! It's always good to embrace a lifetime of learning, John! 😉

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