A Complete Guide to Sanitizing Your RV Fresh Water Tank

The RV fresh water tank is a closed and humid space. And High temperature and moisture, make the bacteria grow quickly on the inside walls of the tank and even in the water lines, so you should consider following a time schedule for sanitizing the fresh water tank.

You’ve got your RV and you’re ready to hit the road! But before you do, there’s one thing you need to do that most RV owners don’t: sanitize your fresh water tank.

Trust me, The last thing you want to see in your RV fresh water tank is some floating algae and fungus, or your drinking water taste is weird,  especially when you go off-grid without any hookups. 

That’s because your freshwater tank is the optimum environment for those bacteria and these little things to grow and live.

Even if you’re not using this water for drinking, let’s say when taking a shower or washing fruits and vegetables. This does not mean you will get sick, but the risk is still there, especially for weaker and old people. 

To start sanitizing your fresh water tank, you need some kind of bleach or a chemical compound to kill bacteria, while many recommend using bleach. In contrast, others are a little bit concerned about it, but if we look at the regulations, it is Ok to use bleach, but in specific amounts.

how often to sanitize rv fresh water tank

The answer is simple: the CDC recommends sanitizing your fresh water tank every three months.

It’s important to remember that your fresh water tank is not a sterile environment, and it needs to be cleaned regularly to protect your health and your family.

But, if you’re going to be using your RV for more than one trip, it’s important to sanitize the fresh water tank each time you use it. This is because, unlike a house, there isn’t a lot of airflow in an RV. So if you don’t take care of the tank, mold, and mildew can grow in it.

Also, If you’re filling up at a public water source like a campground, then we recommend sanitizing it every time you refill the tank. This will help prevent any kind of contamination that may have happened during transit or storage.

how much bleach do you use to sanitize an RV fresh water tank?

What if I used too much bleach?

Nothing really happens, but the problem will be with the fittings, the rubber, and the metal parts, they may damage over time. It won’t be that big damage, because you are going to leave it inside the tank for just 8 hours and flush it away, but it is not a good thing to do.

AND PLEASE, DO NOT USE VINEGAR THINKING IT IS GOING TO NEUTRALIZE THE EXCESS BLEACH IF YOU USED MORE THAN 1 CUP PER 50 GALLONS.

If that’s happened and you used a little too much bleach, that’s ok, do nothing. That’s because mixing these two ingredients will produce chlorine gas, which is extremely dangerous.

Where and at what time should I start the sanitization process?

Being in a campground where you have full hookups makes the process so much easier, you will be able to easily drain bleach water into the sewers and you can refill very easily, and I don’t recommend doing that on a move day, this will create another level of challenges that we don’t need.

The best time to start sanitizing your RV water tank is at night, you add the bleach into the tank, and let the water run through your system and leave it for the entire night for 8-12 hours.

Tools you will need:

When you’re cleaning and sanitizing your RV’s fresh water tank, there are a few tools you’ll want to have on hand.

WHICH DEVICES SHOULD YOU BYPASS BEFORE SANITIZATION

Should I bypass the bleach water from the water filter, dishwashing machine, and other equipment?

The answer is: Yes, you should do that as long as you have a bypass valve available in the connection to the equipment or the machine, but if there is no bypass valve, we have to follow certain steps according to the machine that you have:

For a water filter: you should bypass the bleach water from the filter system, it’s crucial, turn on the bypass valve ON and let the water circulate away from the filter.

But if you cannot find that bypass, try to remove the filter from the canister and put the canister back again without the filter,, start the sanitization process and after you flush the bleach water completely, you can put the filters back inside the canister.

For an Ice maker: it should be bypassed, just turn the bypass valve or check the diagram for it.

If you’re not able to bypass it, you have no option other than letting the bleach water into the icemaker, it’s Ok, you can let it in, but you’re going to end up having ice cubes with bleach water, we’re going to throw that away and wait until we rinse everything and get rid of the bleach and get clean water and clean ice cubes.

For a washing machine: Same thing applies here, try to bypass the bleach water, if you can’t, you can simply let the bleach water into the washing machine, turn it ON on a small cycle, and let the bleach water set there for the whole 8 hours then rinse.

For a water softener: You should bypass the bleach water, and the way to do that, just unplug the IN and OUT hoses from the water softener, connect them together, start the process and after you finish it, connect the hoses back to the water softener.

Before we get into the steps, make sure you followed all the previous tips regarding the bypass

How TO SANITIZE RV FRESH WATER TANK

Step 1: Drain all the water in the fresh, gray, and black water tanks

For fresh water tank:

1. You first should make sure the water heater is turned off.
2. Turn on all the faucets and if you have an outer shower, make sure you open it too, so you don’t have any water left in the pipelines.
3. And connect your RV from the low point drain as usual and drain all the water out.

For gray and black water tanks:

That’s the one that scares most of the new RVers, I hate that part too, simply, the black water tank, if you don’t know it, it is the tank that holds all the wastewater from the toilet. 

It should be drained by using a sewer hose connected to it. There will be a specific outlet for those tanks, and it must be drained in a dump station or in the sewers, and from my point of view, make sure to pick a campground that contains a dump station for that purpose.

Step 2: Add the bleach water to your fresh water tank

Grab the bucket and fill it to ¾ of it with water and then add the bleach according to your tank size, if you have a 100-gallon tank, you will need 2 cups of bleach, or simply, if you have a liquid measuring cup, 2 cups equal to 16 oz.

We just add the bleach in a bucket to dilute it in case some bleach touched your clothes or your skin.

If you have a fresh water inlet or a connector, you will connect the hose and the funnel and add the bleach mixture to it. 

That’s it!

Step 3: Connect your RV’s fresh water tank to the city water and fill it up.

Now we have the bleach water ready to go through our entire water system. 

Make sure you turn on your fresh water valve to “tank fill” or to the filling position to release any pressure inside the pipes.

If you cannot find the valve or you don’t have one, simply keep your faucets ON while filling the tank, in that way, there is no pressure while filling.

Turn OFF the water pump while filling.

When we finish filling the tank, we can turn the fresh water tank valve back to the normal position, or simply, close the faucets back again, and turn the water pump ON.

Now we have the water inside the tank only, we need to circulate in the system, so you will have to turn on every faucet in our RV for some time, until you smell bleach in it, then close it. That way, we guarantee that the bleach water reaches every bit of our water system.

how long to leave bleach in rv water tank

We will leave everything sitting for 8-12 hours or the entire night.

REMEMBER, THIS WATER CANNOT BE USED FOR ANYTHING EXCEPT FOR THE TOILET.

Step 4: Drain all the bleach water

Now we need to flush all the bleach water. Close the water pump, and make sure the tank valve is turned to normal.

You don’t want to drain your fresh water tank on the ground, because it is going to be a total mess. You can connect the fresh water tank with a sewer hose using an adapter and drain it directly to the sewer.

Step 5: Refill, Rinse and Drain

Normally, you will need to do this once, we will rinse and remove all the bleach smell inside the tank, once you fill the tank completely, open the water pump, run all the fresh water inside the water lines like we did before, and drain the rest of the water inside the fresh water tank to the sewer.

That way, we made sure that the bleached water inside the pipes is cleaned and the fresh water tank is sanitized properly.

After all, you can refill your tank again for normal use.

Step 6: Get back everything to normal

Install your filter back into the canister, turn on your water heater, and hook up everything that we bypassed back to normal.

Should you sanitize the RV hot water heater

The answer is: NO, try to disconnect and bypass your water heater away from the bleach water, and the reason for that is that the inner body of the water heater is commonly made of metal, and bleach can react with the metal to create rust, even if it is made of stainless steel, it can become corroded when exposed to bleach.

Check this guide to know how to clean an RV Water Heater

How to use RV fresh water tank tablets

Having liquid bleach is not a convenient thing, they have a strong smell, they’re heavy and they can spell when used,  but instead, bleach tablets make it easier to clean the tanks because they’re very small, they don’t take much space and they’re odorless, above all, they’re safe to carry in your hand.

They turn into liquid bleach when dropped into water.

Most of the bleach tablet brands have that ratio of 1 tablet = 1 cup of liquid bleach. But you should check the label on the tablet pack to know the ratio

To use it, just drop the tablet into the fresh water tank by any mean, whether by the hose, or directly by the funnel to the tank. 

If the tablets don’t fit into the hose or into the tank inlet, you can crush it up inside a plastic bag and insert them as a powder.

Coclusion

Cleaning the RV fresh water tank is an essential part of RVing, it may seem like a tedious task to do but when done multiple times, you will become a pro.