Sanitize Your RV’s Freshwater System In 5 Simple Steps 32227

Your RV’s tanks need to be in proper working order for you to be able to enjoy camping to its fullest, especially the freshwater system. The freshwater system on your RV not only needs to work right, but it needs to be clean, too. Without a clean freshwater system, you’re asking for a trip filled with illness. Like any other part of your RV, your freshwater system needs to be cleaned.

Each year, usually in the spring, when you get your RV out of storage, you should sanitize the freshwater system. It might sound like a hassle, but the last thing you want to do is have unhealthy water in your freshwater tank due to lack of sanitation.

The Steps to Sanitize Your Freshwater System

filling the water tank of a campervan in campground area

Sanitizing the tank will ensure that you stay happy and healthy. It’s honestly not that hard to do. While you can always pay a professional to do it, there’s really no need. It doesn’t require any special tools. All you need is a measuring cup, a funnel, and some household bleach.

From there all you need to do is follow a few simple steps. Here’s they are:

Step 1: Turn Off Your Water Heater and Drain Your Freshwater System

You don’t want to drain the freshwater system with the water heater on. This will damage the water heater. You need to turn it off and let it cool before you drain the water. It’s not a bad idea to have the water pump on to ensure you can get all of the water out of the system before you start sanitizing.

Step 2: Calculate the Amount of Bleach You’ll Need and Add It to the Freshwater Tank

You’ll need 1/4 cup of bleach for every 16 gallons of water in your freshwater tank. This also equates to one ounce per eight gallons. Make the calculations based on those ratios. That means. If you have a 20-gallon freshwater tank on your RV, you’d need 2.5 ounces of bleach to sanitize your system.

Don’t add the bleach straight to your freshwater tank. You should dilute it first. Take that amount of bleach you’ve calculated for your specific RV and add it to at least a gallon of water. Then pour this water-bleach mixture into the freshwater tank with the help of a funnel.

Step 3: Fill the Freshwater Tank with Potable Water and Pump It Through The System

The next step is to fill the freshwater tank with clean, potable water. Make sure to fill it all the way. This will ensure that the tank and the rest of the system get fully sanitized.

detailed view of a water tap in the kitchen inside a caravan, switzerland

You also need to make sure the water with the bleach solution gets all the way through the system. Turn on all the faucets to ensure the bleach water makes its way to every part of your freshwater system. Once the water is circulating through, you can turn them off again.

Step 4: Let The Water Sit For 12 Hours

The solution will take time to really sanitize your system well. You can’t just run some bleach-water through your freshwater system in a few minutes and call it good. I suggest letting the solution sit in your freshwater system overnight. It’s a great way to make sure it gets the job done.

Step 5: Drain the Tank and Then Flush the System

After at least 12 hours of letting the RV sit with the bleach solution in the freshwater system, you need to drain all the water out again. Then refill it with fresh water and start circulating that water through the system with your water pump. Open all the faucets and flush the system until you can no longer smell the bleach.

It may take a few times for you to get all of the bleach smell out. Don’t worry about doing this step multiple times. I’d suggest continuing to flush the system even after the bleach smell is gone. This will ensure you eliminate all of the sanitizing chemicals from the system.

Once that’s all done, I’d suggest replacing any water filters on your rig. After you’ve replaced those filters and switched your water heater back on, you should be ready for another full year of camping!


What’s been your experience sanitizing your RV’s freshwater system? Leave a comment below!

Sanitize your RV's freshwater system in 5 simple steps

Wade divides his time among various outdoor activities in both urban and rural environments. An adventurer by nature, he is always up for a challenging hike, fun hunt, or day out on the water with friends and family. When he isn’t enjoying the outdoors, he’s writing, reading, or tinkering with motorcycles and cars.
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47 Comments

  1. FIRST Check to see the clamp on the filler tube on the inside of the camper is tight, I didn’t and filled the kitchen side of camper and underbelly with water. I’ve been told the clamp being loose on new models like mine are not uncommon

    1. What is the clamp on the filler tube? I’m not sure I understand this? Can you help me? We just got a new RV and wanna make sure to check that.

  2. My RV has a check valve or some type of valve that prevents pouring into the fresh water fill fitting. How do I get the bleach into the system?

    1. You pour the bleach into the water hose befor you hook up to camper. Then turn water on to fill and presto the bleach goes right in with the water.

      1. I’m going try a garden fertilizer injector from AMZ. I calculated that a 50G tank requires .78G of bleach (at 1/4c per G). The injector works at a 16:1 ratio, so the bleach should all be taken up with about 12.5 G of water, then let it continue to run as water-only to full. The injector is already performing dilution, so you should be able to drop the dip tube into straight bleach.
        One commenter said the injector didn’t draw well at his high hose pressure, and recommended only opening the spigot partially to find the best flow. I will probably just use one of my RV pressure regulators on the upstream side of the injector to address this.

    2. Use a drill mounted pump you can get them from a hardware store.
      Thats how i do mine pump the bleach and water solution from a gallon jug.

    3. Some manufacturers (I have a Keystone Montana) recomend you remove the overfill vent cover and pour the bleach in there. They also recommend removing that cover when filling the freshwater tank to prevent air from getting trapped.

    4. It doesn’t have a fill port besides the city water connection? If not then you can get a piece of 2”pvc pipe from a supply store and the proper adapters for the hose, fill the pvc pipe like a mini tank with the chlorine solution.

  3. Attach the white water hose (mine is 25ft) to the Rv fresh water intake valve. Pour the diluted bleach into the other end (unattached) of the white hose (make sure the unattached end is higher than the end attached to the RV. Then attach the hose to the fresh water faucet and turn it on. This allows the bleach solution in the hose to flow into the tank.

    1. Hi Frank, I believe it varies from manufacturer to manufacturer, I’d check your owner’s manual or contact a Camping World service center.

    2. Don’t turn on the water pump until the water tank is full with the correct ration of bleach. You don’t want to run a concentrated solution through the water lines.

  4. The first step on this is to turn the water heater off; but on another video, they said to turn off certain valves for the water heater. Can this simply be done by the inside indicator panel ensuring the water heater is off? Is that sufficient enough for having the water heater off when sanitizing the fresh water tank?

    1. No that won’t keep the bleach water out of you hot water heater. You have to bypass the hot water heater, by doing that water is not going into the water heater.

  5. I started the process , got the bleach solution in & circulated through the entire system, but was interrupted before emptying the bleach solution from the holding tanks. Does it hurt anything to leave the solution in the tanks and not flush the system for a few days?

  6. I have a sulfur and rotten egg smell in my fresh water system. Will this process with bleach take care of that and should I pump this bleach mixture through my water heater also?

  7. When draining the water, do I drain the grey water tank once I run the water through or if I still smell bleach, do I drain the fresh water tank

  8. The bleach water will not go into the fresh water tank through a funnel. How do I get the bleach water into the freshwater tank?

  9. I just bought a ’97 Itasca. It has issues, and one of them is that when I run the water faucets, foam or suds come streaming out. What up? Di the previous owner try to clean the system with soap? Does not look potable. Referring to the article above, can I just keep flushing the system util the suds go away?

    1. RV/Marine antifreeze in the system looks like pink foam when you rinse the system clean. (previous owners “winterized” the system)

  10. Yes it’s true. But far more worrisome is bacterial growth in your system. As long as you don’t overdo the bleach (make a solution as instructed above) and let it sit at least 3 hours before draining and flushing ( you can go longer but I would not go over 24 hours if possible) your system should be fine.

  11. I have a new trailer- first time. Do I need to flush out the antifreeze in the lines before adding the bleach water?

    1. I would recommend doing so. That will allow the bleach to do it’s job better and won’t cause any concerns with mixing bleach and antifreeze (I don’t know if that would be a problem or not, but best to avoid doing it).

  12. I was told to use vinegar, not bleach. Anyone done this and what is the ratio to use. Also how long to keep in the tank?

  13. I do mine every spring and just completed the process. These instructions are for a winterized RV. Don’t make this harder than it is. To get rid of the RV antifreeze, first, I hook up the hose to the city water connection. Turn on the hose to pressurize the system. Inside open all the faucets and shower head, I even do the toilet. Once the antifreeze is purged from the system, I fill the onboard water tank with water (100 gals). At the same time, I pour approximately a pint of bleach in the side water fill. (Mine doesn’t have a check valve). Once the system is full, I remove the hose from the city water connection and turn on the water pump and again open all the faucets, shower and toilet to circulate the bleach water. Let sit 12-24 hours. Dump, refill, circulate and dump. I do this twice. Don’t forget to make and discard several batches of ice if your RV is so equipped. Also, if you have a washer, run the first load with an old towel or similar as it will most likely have some residual antifreeze trapped in the line. I learned from my mistakes. I hope you don’t have to. Have a great season!

  14. I left water sitting in the Grey tank for about 2 years without using it and I am concerned it has a lot of bacteria or algae. Will this work to get it cleared up. I don’t even want to run it thru my system. Just get it cleaned up and dump it.

  15. Your “grey” tank is waste water from your sinks and shower. So if you are talking about your “grey” tank and not your “fresh water” tank I would not worry that much about it. Just fill it and flush it a couple of times with a light detergent and water mixture. But if you are talking about your “fresh water” tank it’s a different story.

  16. Once we drain the bleach and refill to get the bleach out
    Do we drain tank completely or leave some water in tank even if we are not using rv at that time?

  17. When you say “drain” or “empty” the fresh water tank after running water though the system and letting is sit, do you drain through the low point valve under the trailer or just continuously run the pump and water through the faucets until tank is empty? Thanks.

    1. Run the water pump and drain the tank through the system to clear the bleach out of the lines as well as the tank.

  18. I have a 93 Itasca Sundancer. I don’t have the availability to bypass my water heater. Will the process be ok with the water heater.

  19. We have never used the fresh water tank. This is our 4th summer with our RV. Should we do this only when we want to use the fresh water tank?

    1. Hi Kathy, Remember that hot, warm dark and humid conditions are perfect breeding spots for mildew and bacteria to grow, so the more you sanitize and disinfect the better you are. I believe the warmer climate requires you sanitize more often. Remember, your fresh water tank has a overflow valve or opening near the top two inches of your holding tank so your filling the tank still is not adequate, you need to drive around and swish the water, I do my Monaco’s 100 gallon tank with only 20 to 30 gallons of water and the swishing gets it all and including the top of the fresh water tank and I have not wasted 100 gallons of water.

  20. We sanitize the tank after we drain the tank of antifreeze when we open the camper in the Spring. How often do you recommend sanitizing during camping season? We usually camp May- October.

  21. I live in an apartment complex without access to an outside water outlet, nor any place to dump. Any ideas where I can do this process? It seems a little inconvenient to do this in the middle of a camping trip.

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