Can You Put Bleach in Your RV Holding Tanks?


bleach in holding tanks lg

RVs can require a lot of maintenance and preventative care. And in our homes, we often use bleach to clean lots of things. But can you put bleach in your RV holding tanks?

A bleach and water solution is a great way to clean and sanitize an RV’s holding tanks. It can help remove bacteria build-up and other waste products that cause the holding tanks to smell. 

But that’s not all there is to know about caring for your holding tanks.

After all, how much bleach do you use? Is too much damaging to the plumbing? And are there safer or better alternatives to bleach?

Just keep reading!

Will bleach harm RV plumbing?

When used correctly, bleach will not harm RV plumbing. Mix ¼ cup of bleach per gallon of water. Ideally, fill the black and gray water tanks with this solution, allow to sit for 8 hours, and then flush with plain water.

Not sure how big your tanks are?

They vary a lot by manufacturer and type of RV, but here’s a general guide. Start small, and monitor the fullness levels on your panel to make sure you don’t overfill them.

Type of RV Average Black Water Tank Size Average Gray Water Tank Size
Travel Trailer 30 gallons 40 gallons
Fifth-Wheel 60 gallons 60 gallons
Class B RV 15 gallons 20 gallons
Class C RV 40 gallons 50 gallons
Class A RV 40 gallons 60 gallons

If you haven’t cleaned your tanks in a long time, letting it sit overnight might be even better.

A good time to do this is right before heading on a long drive. Or after a long period of sitting before a big trip. Driving to your destination will give the solution a chance to slosh around and break up any residue left behind.

Then, when you get to your campsite, dump it at an approved dump station.

Completely drain and rinse the holding tanks. If you don’t rinse the tanks, it won’t hurt the plumbing, but it could cause gaskets to dry out faster. Dumping your black water tank, cleaning it, and sanitizing it can be a hassle.

But how long can you leave black water in your tank?

If you leave it too long, then it can start to smell and even back up. To read more about how long you can leave black water in your tank, check out this recent article.

Just click the link to read it on my site.

Why does my RV bathroom smell like a sewer?

RV bathrooms can smell like a sewer if the black water tank has not been emptied or cleaned recently or if the drain hose is connected but not able to flow freely to the sewer drain.

Black water is the water that drains from your RV’s toilet. It holds all the water, urine, and fecal matter from the toilet.

To read all about what black water is, as well as gray water, and how long you can go before dumping your tanks, read this recent article. What really surprised me was how nasty the gray water tank can get.

Just click the link to read it on my site.

If you’re not dumping your black water tank regularly, it’s going to start to smell. You also need to have enough water in the black water tank to prevent the solid waste from drying out. If the solid waste dries out and builds up, it will not only start to smell, but it could damage your tank too.

An easy way to add water to your tank is just to add water each time you flush the toilet.

You can also add specialized holding tank chemicals that will help break down toilet paper and fecal matter. Finally, keep it clean. Make sure you use RV toilet paper to prevent clogs. Clean and sanitize your holding tank.

Clean the toilet and the flapper thoroughly.

Can you put dish soap down an RV toilet?

A small amount of dish soap flushed down the toilet is an environmentally friendly and inexpensive way to clean the black water tank.

Dawn dish soap, specifically, can be used as a household cleaner, stain remover, bathroom cleaner, and even for black tank maintenance.

The main reason I mention Dawn dish soap is that it is environmentally friendly. It’s safe and biodegradable. It’s also gentle and non-corrosive.

So, while it may not be very effective to clean and sanitize your tank, it can absolutely be used as routine maintenance. A small amount in a freshly dumped tank will help cut grease, eliminate odors, and soften any blockages.

You should also be sure to use biodegradable toilet paper in your RV toilet.

While technically, all toilet paper is biodegradable, RV toilet paper is specifically manufactured for use in RV holding tanks. It is faster dissolving and will help prevent clogs or sensor errors.

To read more about why you should use biodegradable toilet paper in your RV, check out this recent article. I also covered whether or not paper labeled “septic-safe” is acceptable.

Just click the link to read it on my site.

Is Borax good for RV holding tanks?

Borax is not ideal to put in RV holding tanks as it kills all kinds of bacteria, including the beneficial bacteria that helps break down fecal waste. This can lead to waste buildup and a clogged black water tank. However, Borax can work well down sink drains into the gray water tank.

You need bacteria and enzymes in the tank to break down the waste.

Borax is a great product for household use in general. It cleans and reduces odor because it is a natural antibacterial agent. It can also be used to prevent mold.

However, it may not be appropriate to use in your black water tank.

Using Borax is great to clean your black water tank. It is gentle and won’t hurt your tank. You can fill your tank with a Borax and water mixture before a long trip to clean the tank. The sloshing around while you’re driving will help get any residue off the walls.

But it shouldn’t be used as routine maintenance. That could actually do more harm than good.

How do you clean and deodorize RV holding tanks?

Diluted bleach and dish soap make excellent ways to clean and deodorize black and gray water tanks in an RV, and Borax is good specifically down sink drains to clean and deodorize gray water tanks.

Once you’ve dumped your tank, you can add a mixture of bleach and water to your tank.

Put ¼ cup of bleach for every gallon of water you put in your tank. Fill it with this bleach and water mixture and let it sit for at least 8 hours to get it nice and clean.

Then dump it at an appropriate dump station and rinse until you don’t smell bleach anymore.

But my favorite way to clean and deodorize my RV holding tanks is with these Camco TST Ultra-Concentrated Drop-Ins from Amazon.

These pods don’t require any measuring or mixing. I just drop one in my tank, and it eliminates odors and breaks down waste.

Just one pod treats up to a 40-gallon tank, and they are biodegradable. One pod added to the toilet at the beginning of each trip keeps everything smelling nice and fresh.

It’s also great for when you leave black water in your tank too long. If you have been boondocking or just haven’t dumped your tank in a long time for whatever reason, you can add two pods to your tank.

Flush your tank out really well, and the smell will be gone in no time.

RV 101® - How To Sanitize the RV Water System Using Regular Household Bleach

Did I answer everything you wanted to know about whether you can put bleach in your holding tank?

If your RV smells funky, it might be time to clean and sanitize your black water holding tanks.

When you clean your tank, be sure to give the toilet and the flapper a good scrub, too. Dawn dish soap is a great way to cut grease and an environmentally friendly solution to help clean your black water tank.

If you’re not planning on going out on the road for a long period of time, take the time to clean and sanitize your tanks before putting your RV in storage. You’ll be glad you did.


Image by OpenClipart-Vectors from Pixabay

Jeff Campbell

Jeff Campbell travels on and off with his 3 daughters in a Newmar Baystar Class A Motorhome. He writes extensively on both RVs, campgrounds, parenting on the road tips, remote learning & schooling, and much more!

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