How To Sanitize RV Water Tank

Last Updated on 05/13/2023 by Glynn Willard

The first point to make is “why sanitize your fresh water tank in a camper?”

There are many resources about how to sanitize your camper water system for good reason.

And for the most part, I haven’t seen anything realistic that wouldn’t work.

But is it necessary to buy an RV water sanitizer product to sanitize your tank? Absolutely not!

Let’s look at my favorite tried and true method to keep your drinking water safe in your RV.

What’s The Primary Goal For RV Water Tank Sanitization?

First and foremost, the elimination of pathogens.

This is not about changing the flavor of your water, which you can do with either an inline filter, external water filter or by filtering the water as you fill your fresh water tank.

We preferred the last of the three. We did this only to standardize the flavor of the water from different sources.

There are a lot of living organisms that can flourish in your fresh water tank.

Some are harmless, some elicit foul odors and others can be downright dangerous.

Therefore, killing the dangerous and odor causing microorganisms is why we sanitize our campers fresh water tank.

How To Sanitize The Fresh Water Tank In An RV With Bleach

I’m specifically discussing the use of household bleach in this article.

This means a bleach you can acquire at the grocery store. You can obtain higher concentrations of bleach that are far more caustic elsewhere.

Do not use these. They lower the pH too much and can damage your system.

So, just stick to grocery store bleach with no additional additives or scents and you’ll be fine.

If you look closely, you’ll see most household bleach contains between 4.5% and 5.25% sodium hypochlorite.

That’s what you’re looking for.

How Much Bleach To Sanitize RV’s Fresh Water Tank?

Your goal is a solution of water containing 50-200 ppm of bleach. I think closer to 200 is too much.

Side note. For you chemistry nerds out there, remember, if you’re not part of the solution, you’re part of the precipitate. I couldn’t resist!

If you want to be precise, use this site’s calculator.

First, look at your bleach to find the percentage.

Then, on the calculator, enter the percentage, your desired ppm (50-200), total volume of your fresh water tank and your preferred metric output (gallons or liters).

If you don’t feel like using the calculator, here’s an example:

If you have a 50 gallon fresh water tank and you use a bleach containing 4.5% sodium hypochlorite and your goal is 100ppm, use the following amount of bleach:

1.9 cups of bleach for a 50 gallon tank.

You can round that up to 2 cups. And remember, that’s for 100ppm.

Steps To Sanitize Fresh Water Tank In An RV

Sanitizing your fresh water is too easy to skip (and too dangerous to ignore).

As stated before, your goal is a solution of between 50-200 ppm of sodium hypochlorite to eliminate dangerous microbes in your fresh water tank.

We’ve found 50-100ppm to work just fine.

Empty your fresh water tank.

Remove any inline filters. This is easy with canister based filters. Simply unscrew, remove the filter and replace the empty canister.

Add the appropriate amount of bleach to the fresh water tank. I describe this above.
Fill the fresh water tank with water just until it starts to overflow.

Allow the bleach treated water to reside in your fresh water tank for a minimum of 4 hours.

Manually bypass Your hot water heater.

Draw the treated water through all of your faucets using both the cold and hot water handles for 30-60 seconds. This is why we bypassed the hot water heater.

After a total of four or more hours, dump the water from your fresh water tank.

Refill the tank until it overflows and let it sit for a few minutes.

Draw some of this water through all of your Pex lines to start flushing the bleach out.

Dump the fresh water tank after a few minutes.

Refill the tank until it starts to overflow.

Draw water back through the faucets until the smell of bleach diminishes.

Your water is now safe to drink. If it still smells or tastes a little too much like chlorine, you can fill and drain the tank an additional time.

A Few Points About Using Bleach For Your Fresh Water Tank

Bleach is an ideal disinfectant because:

Bleach has been used as a water disinfectant for over 100 years.

It’s very inexpensive and readily available.

It has a very broad antimicrobial property.

Bleach is persistent in treating potable water.

It’s easy to use.

You’re not drinking the chlorinated water used for treatment.

Bleach is not toxic at low concentrations to humans.

Alternatives To Bleach For RV Fresh Water Tank

A quick search on Amazon reveals a lot of bleach alternatives ranging in price.

You’re free of course to use whatever you feel suitable, but you can still safely accomplish the same thing with bleach for far less money.

And it takes very little time for the chlorine smell to dissipate.

How To Sanitize RV Fresh Water Tank When Fulltiming

Sanitizing your RV’s fresh water tank at your homebase is easy.

But what if you don’t have a homebase? We solved this problem by booking a night at a campground.

I always tried to align the process with a rainy day to dilute the smell and the impact on the environment.

I also advise you not to mention your intentions to the park’s management.

Is it environmentally friendly? No. Is it overwhelmingly bad for the environment? No.

But for the sake of our family’s health, some sacrifices are necessary.

Do I Need To Sanitize My Fresh water Tank If I filter My Water In An RV?

Yes, microbes still find their way into your tank.

Most filters do not remove some of the most harmful pathogens. If you have an inline UV based filter, it will do the job.

But your tank may still develop a foul odor. So, this is another reason to treat your fresh water tank periodically.

How Often To Sanitize Fresh Water Tank In An RV?

This is a loaded question because it depends on your usage, if the RV was in storage, environmental temperatures and whether it was ever filled with contaminated water.

We treated ours every 3-6 months depending on the environment where we live.

As long as we maintained a 3-6 month consistent sanitization, we haven’t had any problems.

Wrapping Up Sanitizing Camper’s Fresh Water Tank

Sanitizing your campers water tank is crucial to eliminate harmful microbes and eliminate foul odors.

The least expensive way is to use regular household bleach. We’re talking pennies per treatment.

Figuring out the right amount of bleach to use for your RV’s tank can be determined with this calculator.

Remember, you’re looking for 50-200ppm concentration of sodium hypochlorite to total water in your tank.

Leave it sit for about four hours, dump it and flush it several times and your campers water system will be sanitized for safe drinking.

We appreciate any help we can get to bring you great content. Donate or buy us a coffee on our Ko-Fi site.