New device keeps your fresh water tank clean. So simple, yet effective!


By Tony Barthel
Using bleach to sanitize a fresh water tank in an RV is something that has become customary for many. But the process of bleaching a fresh water tank has consequences, such as unusually white shoes and clothes. It’s not as easy to sanitize a fresh water tank when you’re worrying about getting bleach all over you or your RV. Here’s where the RV Inline Sanitizer comes in handy. 

RV inline sanitizer
The RV Inline Sanitizer with bleach tank cap open.

Recently Tom Hoepfner reached out to us to give his device a try and I have to admit my first thought was this was definitely a first-world problem solver. But after using it, I realized he had really saved me a lot of time. And, with fewer bleached articles of clothing, potentially a lot of money as well. 

Essentially the RV Inline Sanitizer is the simplest of solutions. It’s essentially a reservoir in which you put bleach and then use a source hose and a delivery hose to fill your fresh water tank. The sanitizer effectively adds the bleach as you fill the tank. It truly is that simple. 

The recommendation is to use the sanitizer before you head out on a trip so that the bleach can slosh around in the tank while you navigate the highways and byways of this majestic land. Then, once at your destination, flush the tank with fresh water until all evidence of bleach is gone. 

The mixture recommended is 8 ounces of household bleach for every 40 gallons of fresh water. There are some who might argue that household bleach is not really meant as a food-grade product, but when I owned a bed and breakfast, bleach was a part of everyday use in the kitchen, since we used it to sanitize sinks and prep tables. It’s just what we use ‘round here. 

Anyway, once your fresh tank is full of the bleach/water solution the recommendation is to disconnect from city water, turn on your water pump and run each faucet in the RV until you smell the bleach. Then do the slosh and drive. 

Once you arrive at your destination flush out the system with fresh water until you no longer smell the bleach. Simple. And the RV Inline Sanitizer really does simplify the process – it’s a much more useful gadget than I had anticipated, honestly. 

Surprisingly, I do know someone who got pretty sick from the water in their RV and it turns out they never sanitized the tanks in the five years they owned it. For those who don’t drink the water in their RV, remember that your skin is the largest organ on the human body and you likely do use that water to take a shower and even brush your teeth. 

It is recommended by many manufacturers to sanitize the tank twice a year. 

So is the RV Inline Sanitizer worth the money? That’s your decision, but I have to admit that having it has made me more likely to sanitize the tank in my own RV. It’s a simple solution that makes something we all should be doing a little easier and that’s what RVing is all about, really. 

Learn more on the official product website, or check it out on Amazon.


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21 days ago

Who knew I’d be learning so much but this has brought up a few questions. I hav ore an r-Pod, the grey water drains through the black water tank.

  1. Will the bleachy water damage the water lines?
  2. Will the bleach damage the black water tank and it’s “environment”?
  3. Still don’t know where to dump the water, no place I go has public sewage – it’s all septic systems with tanks so I wouldn’t want to fill up their tanks.

Whew, something so simple as clean water can be so complicated

Tommy Molnar
22 days ago


“Much ado about nothing”.

26 days ago

We have used this system and love it, we drop our bleach sanitized water into the drop station or the RV hopup sewer site, besides 8oz bleach and 20gals or more will never destroy the lawn and shruppey, after all I used as much bleach in my 8 gallon capacity cloth washing machine and it automaticly runs into my city sewer. So what’s the big deal, I love it!

27 days ago

What a gimmick. Just put the bleach in your sediment filter canister, then fill it up with water. Geesh, one more useless RV gadget.

1 month ago

If you’re adding and sloshing bleach in your fresh water tank, then draining it out, where are you draining it to? I don’t see it being good to run your pump to pump the tank dry so you must be draining it out onto the ground. Drain 40 gallons onto the ground at your campsite will make quite a little lake and muddy up the ground or kill the grass.

1 month ago

Bleach will destroy the copper pipes in Aquahot systems. In the Aquahot manual it specifically states not to use bleach.

1 month ago

I sanitize my freshwater tank with sodium-dichlor, 1/2 tsp in the hose then fill up the 40 gal tank. Run it through all the faucets and leave it in overnight, drain and refill with plain fresh water.

Chuck B
1 month ago

I’m not sure how many RV parks would like for us to dump our 100 gallon water tank full of bleach water when we arrive. Chuck

1 month ago

I can just imagine how happy the campground operator is with you flushing your tanks in their sewer system. If everyone did this, it would overload the system.

1 month ago

Glad to see this! My new rig has a freshwater fill where the hose screws on, I can no longer use a funnel to put in bleach.

1 month ago
Reply to  wanderer

Use your funnel to pour bleach into your empty hose. Flush your hose. Disconnect it enough to drain a few feet from the hose then reconnect to the supply. Use the funnel to pour the bleach into the hose, plug it into the vehicle and turn on the water.

Seann Fox
1 month ago

Bleach is a highly toxic environmentally unfriendly substance.
Hydrogen peroxide on the other hand sterilizes just as well as bleach and is environmentally friendly

1 month ago
Reply to  Seann Fox

Would be nice to see some scientific facts about using hydrogen peroxide versus bleach!!

1 month ago
Reply to  Seann Fox

The CDC doesn’t recommend Hydrogen Peroxide for water treatment! Hydrogen Peroxide is an effective sanitizer at the strength you buy in grocery stores. If you could get in your tank and wipe it down using full strength it would work fine.

Several other common products, including hydrogen peroxide, citrus juice, and potassium permanganate, have antibacterial effects in water and are marketed in commercial products for travelers. None have sufficient data to recommend them for primary water disinfection at low doses in the field.” -CDC

Bleach rapidly breaks down when exposed to air or contact with organic material. It is NOT harmful to the environment.

 As bleach is used to destroy germs, it reverts mainly to salty water.
Fred Reiff, P.E., is a retired official of the Pan American Health Organization.

1 month ago

I measure out the bleach and add it to the hose before connecting it to a water source and then let it sit in a full tank for a few days and before I run it throughout the water system but I bypass the hot water heater that I drain after the end of our last trip.

1 month ago

If you have a water filter you already have an in-line sanitizer canister. Remove your in-line water filter from it’s canister. Fill the empty canister with your measured amount of bleach and reinstall canister. Fill fresh water tank and run faucets till you smell bleach.

1 month ago
Reply to  Dave

This will not work with most of the setups I have seen… for example – the in-line water filter on Thor motorhomes is only functional when hooked up to city water and is separate from the fresh water tank… the fresh water tank filter is found at the water pump… also this does not do your fresh water tank… it needs bleach added at the exterior fresh water tank fill… you need to know how that maze of hoses is hooked up before thinking adding bleach to the in line filter canister will sanitize a water system…

27 days ago
Reply to  Larry

My filter filters any and all water whether you are using city water or filling your fresh water tank. Not sure why Thor wouldn’t want to filter the water going into your frash water tank.

1 month ago
Reply to  Dave

Good point Dave but my canister filter is big. It needs a huge circular wrench to open it and then remove the filter. Most people don’t have this jumbo-sized one so it may be easier. I like this new thing which doesn’t require any messing around.

27 days ago
Reply to  Drew

My filter canister is about 4″ in diameter. It came with a filter wrench and is not extremely tight. This is also a goot time to install a new filter element.