How to Clean Your RV Holding Tanks

Imagine getting your RV out of storage to prepare for your next road trip, and as soon as you open that door, the green smog comes rolling out, hitting you right in the face. It smells like something horrifying has been sitting in your toilet since the last time you used it. You gag, your eyes watering, as you wonder if something crawled into your beloved motorhome...and died.

First and foremost, identify the offending odor 

From personal experience, the smell created by a lack of cleaning prior to winterization or lack of maintenance is similar to the stench of rotten eggs. Take it from seasoned RVers and homeowners alike: you want to avoid this scent at all costs or risk permanently traumatizing your nostrils.

First, you need to figure out where the smell is coming from. The sewer smell can come from several different places, and once you know where it’s coming from, it’s easier to fix the problem and make your camper feel livable again.

The most likely culprits include the p-traps, black water tank, or fresh water holding tank.

If your p-traps are stinky

P-traps, a kind of pipe found in travel trailers, fifth wheels, some RVs, and in our homes, are pieces of plumbing specifically designed to trap bad smells. P-traps work because they hold a small amount of water that blocks the gaseous smells from entering the area above them. When the water dries out of the p-trap, either because the RV has been in storage for a long time or because of dysfunction in the plumbing, smells can seep into the space.

Though it sounds intimidating, maintaining the p-traps in your RV is actually pretty simple and can help prevent bad smells.

1. First, find an empty gallon jug and fill it up with water
2. Mix in a cup of baking soda or white vinegar
3. Pour the water and baking soda or vinegar mixture down all the drains
4. Marvel as the smell disappears

After you do this, remember to keep some water in the p-trap to prevent sewer gases from wafting up through the drain. Make sure to perform this maintenance when you take your RV out of storage. Remember that a small amount of water in the p-trap is necessary for it to function the way it's intended!

Think it's the black tank?

If you find that the smell is coming from your toilet, it most likely originates from your black water tank. The black tank requires a balance of water, waste, and ventilation to remain functional and smell-free. If the waste doesn’t have enough water to help it move freely, then it can get stuck to the sides of the tank. This could prevent it from being flushed out when you dump your tanks, which, in turn, can lead to extreme buildup until you have a clogged mess on your hands. 

As you can imagine, the stench a clogged black water tank creates is nauseating, to say the least. To prevent this from happening, let the water run for a few seconds when you use the toilet. You can also purchase several different chemicals to help break down the waste in your black tank.

The black tank also requires plenty of ventilation through the vent out of the camper's roof. Going down the road, the wind can cause the air flow to be pushed back down, so the only other way for the smell to come out is through the toilet. You can purchase vents that will use the outside wind to help suck the odor out of your black tank. 

And if it’s the fresh water tank…

After filling up your fresh water tanks, you may sometimes notice a terrible smell or taste coming from the sink or shower. The best way to eliminate this is by cleaning and sanitizing your tank. You can accomplish this by following these easy steps:

1. Fill your fresh water tank up 3/4 full
2.  Mix 1 cup of bleach with 1 gallon of water
3. Pour the bleach/water mixture into the freshwater tank
4. Fill the fresh water tank full with water
5. Turn the water pump on
6. Open all faucets until you smell the bleach
7. Drive the camper around, if possible, to let water move around the tank
8. Let the water sit overnight
9. Drain the water out of the entire system
10. Refill with fresh water only
11. Open all faucets again until you don’t smell bleach anymore
12.  Repeat steps 9-11 if necessary to get rid of all the bleach

Cleaning alternatives to bleach and baking soda

Vinegar

• Works well when combined with baking soda
• Great for breaking up mild clogs and neutralizing odors

Hydrogen Peroxide (Food Grade)

• Helps sanitize and reduce bacteria
• Mild foaming action helps clean grime in the trap

Citric Acid

• Effective for deodorizing and removing mineral buildup
• Mix with warm water and flush through the drain

In the end, if you experience a bad smell in your RV, you're unlikely to ever forget to keep your tanks clean and debris-free. Travel trailers, fifth wheels, camper vans, and RVs often sit in storage waiting for the next camping trip. Water and waste left in the tanks can quickly become a breeding ground for bacteria and resulting smells if not emptied after every trip and consistently maintained.

Travel happy and smell-free with Transwest

Want to know what types of chemicals are out there to keep your RV or travel trailer smelling fresh and clean? Contact the parts department at Transwest, and they will be happy to help you find the right chemical or services. 

And of course, if you’re in the market for a new RV, feel free to shop our online inventory or stop by a Transwest location.