A major part of the preventative maintenance schedule on your RV should always include a standard sanitizing routine for your freshwater tanks. If you don’t sanitize your clean water tank, you will eventually pay the price.

Fortunately, it’s not too difficult a job as all you need to do is follow the easy steps listed below and your tank will be efficiently and quickly sanitized before you know it. It doesn’t require anything special or some wild concoction that you can only order online.

You will need bleach, a measuring cup, and a tea pitcher that you don’t want to drink tea out of. You will use it with bleach after all and you can just set it aside as part of your routine maintenance tools, rather than holding the tea in the fridge when you need to get your hands on it.

How to sanitize your fresh water tank in 5 steps

It doesn’t have to be complicated to sanitize a water tank, should it? We’ve done it hundreds of times, and these are the 5 steps we use:

  1. Drain your fresh water tank
  2. Start the cleaning process
  3. Fill the tank completely
  4. Take time out
  5. Flush and drain the system

Let’s dive into the first step which is draining the water tank.

1. Drain your fresh water tank

First and foremost, you have to drain your freshwater tank. You don’t want to add bleach to a full tank unless you prefer to accidentally poison yourself and everyone else.

Here’s how you drain the fresh water tank:

  • Turn off your water heater
  • Drain the water heater once the heating element has cooled
  • Leave the water pump on
  • Close your water inflow valves on the water heater
  • Shut off the inflow valves to anything in the RV that requires water, such as water filtration systems, and ice makers
  • If you don’t have an inflow valve on the filtration system, remove it

You also want to turn off your water heater but leave your water pump on for the time being. Draining your water tank removes water from the water heater and if you accidentally leave it on, it will damage the heating element within.

Once the heating element is cooled off (give it a good half an hour), drain the hot water tank completely. You also have to attend to anything in the RV that accepts an inflow of water from the freshwater tank.

Some refrigerators, all ice makers, and the water filtration systems that are often built into RVs need to be turned off and drained. Turn them off by shutting off the inflow valves which will ensure that none of the bleach solutions finds its way into any of the appliances until you are ready to run it through.

2. Start the cleaning process

Now that you have emptied your water tank, you have to fill it again. Click here if you don’t know how to fill the water tank. Fill the water tank only to about ⅓ or ½ half of its total capacity. For every 16 gallons of water that you put back in, you want a ¼ cup of bleach.

If all your tank holds is 32 gallons, then you can fill it to the halfway point and pour ¼ cup in there. If you are using less than 16 gallons, you can calculate it using ounces if it is easier (1 ounce of bleach for every 8 gallons).

3. Fill the tank completely

Now you’re simply going to fill the tank until it’s bursting at the seams. This is why it’s so important to ensure that all of your inlet valves for everything that requires freshwater are shut off.

When you fill the tank completely, it will force water into those appliances that are open and it is preferable to open them one at a time, smelling for the bleach running through the pipes, to ensure that each one is properly sanitized.

4. Take time out

Now that bleach is touching and sanitizing every aspect of your freshwater system, you can go catch a nap or play Elden Ring for a few hours. Maybe you can weave a survival bracelet or design some paracord jeep handles.

It doesn’t matter what you head off to do, so long as you allow the bleach to work its magic for a few hours or so. It needs to have enough time to properly sanitize your system.

Since you have to go through this waiting period, it’s probably best to sanitize your system when you aren’t camping, like when your RV is parked in the backyard and not doing anyone any good just sitting there.

You can put it to work by sanitizing your freshwater tank and once the tank is full and bleach is in the pipes that run to all of your fixtures and appliances, let it chill there for a good 8 to 10 hours.

5. Flush and drain the system

Now it’s time to drain the tank and get it all out. Since we’re dealing with bleach, you can’t just drain it, fill it, and go on your merry way. It needs to be flushed out and the only way to do that is to have your sense of smell ready to go.

Once it’s drained, start filling it back up. Go to each appliance and faucet and run the water. Make sure that not a single ingress or egress point where the freshwater travels smells like bleach.

If you have someone with you that has a better sense of smell, bring them along for the ride as your bleach sniffer. When bleach is no longer detected, you can completely fill the tank and return everything to the way it was.

Why should you sanitize your fresh water tank?

Two things happen when you fail to periodically clean and sanitize your freshwater tank. First, there’s a strong probability that there will be an algae build-up inside the tank. It’s not the same kind of algae that they use to wrap around delicious sushi on Five-Dollar Sushi Wednesdays at Publix.

Algae build-ups occur if you have clear water lines because algae does require a bit of sunlight to go with the humidity and warmth. So, if you have clear water lines, algae are something that you will have to look out for.

The second thing that you will get from an unsanitary tank is contaminants, which is a purposefully vague word since contaminants can be just about anything. That’s exactly what you’ll get, however, just about anything.

Bacteria is the primary culprit here and not the good kind that comes from yogurt. It’s the bad kind that will have you filling up your black tank pretty fast.

Fortunately, it’s safe to use anti-bacterial products, unlike the products that you use to clean out your grey and black tanks, where harmful bacteria are beneficial for the breakdown of waste.

How often should you sanitize your freshwater tank?

It’s amazing the number of people who will buy water bottles rather than ever drink the water coming from their freshwater tank. The most common complaint is that it just tastes disgusting.

Keep in mind that disgusting it may be but it’s also what you’re using to bathe off with. It most likely tastes disgusting because the fresh water tank isn’t being cleaned enough, not being cleaned well, or not being cleaned at all.

It’s a relatively simple task, so long as you have the patience to allow the bleach and water mix to sit for 8 to 10 hours. Other than that, it’s not labor-intensive and a proper maintenance routine will make the water taste better in the short and the long run.

How to sanitize your freshwater tank without bleach?

bleach bottle
Photo by Kelly Sikkema / Unsplash

Not everyone is enamored with the idea of using bleach in their freshwater tank system. It’s hard to blame them since bleach is associated with gleefully slaughtering everything it comes into contact with.

Fortunately, for those on the other side of the fence, well away from bleach, there are alternatives available, such as Camco TastePURE Spring Fresh Water System Cleaner, heated Hydrogen Peroxide,  and White Distilled Vinegar.

There are three things that you need to eliminate from your freshwater tank:

  • Listeria
  • E.Coli
  • Salmonella

All of these are bad news and they primarily focus on the gut, which means bad things for your backside. The good news is that the above-listed alternatives for bleach kill all three.

When it comes to hydrogen peroxide, it will need to be heated to 130 degrees Fahrenheit before it will kill all three and that’s also the case with white vinegar. The easiest solution is going to be the Camco solution because it doesn’t require any extraneous tasks to unmask its full potential.

On its own, hydrogen peroxide will only kill E.Coli and Salmonella while vinegar alone and unheated will only kill salmonella, leaving E.Coli and Listeria to wreak havoc in your freshwater tank.

Baking soda is also tossed around as a viable alternative from time to time and it is not. You should never include or solely use baking soda to clean and sanitize your freshwater tank.

Final thoughts

All things considered, it’s a pretty simple task sanitizing your freshwater tank. So long as you don’t mind waiting on the bleach to sit. However, you could always start in the evening and sleep the time away, draining and flushing in the morning.

Whatever method you choose, just be sure to do it twice a year and your freshwater will taste as good as anything out of your house tap.