How To Sanitize an RV Water System

TheRVgeeks Annual Maintenance, Maintenance, Plumbing, Water & Sewer 19 Comments

Updated! We show you how to thoroughly sanitize both hot and cold sides of your RV’s fresh water system.

We’ve been drinking the water from our RV’s fresh water tank for over a decade without a problem. It’s perfectly safe to do, as long as you sanitize your fresh water system periodically. We do ours about twice a year (keep in mind that we’re full-timers… those who store their RV all winter should be fine sanitizing once a year, in the spring).

Clean, safe, sanitary drinking water is a breeze when you take a few basic steps to manage the fresh water system on your motorhome, travel trailer of fifth wheel. Fresh, drinkable, potable H2O doesn’t only come from bottled water, but right from your RV’s tank, saving money and plastic in the process.

We’ll show you how to use bleach to kill any bacteria that may be present in your camper’s water system, and have all the safe drinking water you need.

If you saw the first video we made on this topic over two years ago, we only sanitized the cold water lines. That’s because the primary purpose of sanitizing is to make the water safe to drink. Since a lot of people asked about sanitizing the hot side of the system as well, we’re going to do both hot and cold sides today.

You can see the original video here: Sanitizing an RV Fresh Water Tank

If at all possible, the deal time to do this is on a day when you’re planning to take a long drive, preferably down some pretty twisty roads. This will agitate the water in the tank, helping to clean it as you drive, and make sure the top of the tank gets splashed too.

Since we’ll be doing some tank flushing as part of the process, your trip should ideally take you from one full hook-up RV park to another one, neither of which should have drought or water use restrictions.

It’s particularly important to end your drive at an RV park with water hook-ups, since you’ll be arriving with a tank full of bleachy water.

The only supplies we’ll need for this job are some bleach, a 1-gallon pitcher and an old measuring cup.

We're handy RVers, not professional technicians. We're happy with the techniques and products we use, but be sure to confirm that all methods and materials you use are compatible with your equipment and abilities. Regardless of what we recommend, consult a professional if you're unsure about working on your RV. Any task you perform or product you purchase based on any information we provide is strictly at your own risk.

We sometimes receive products for evaluation at no cost, and The RVgeeks are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites. But our opinions are our own, you won’t pay an extra penny, and we only link to products we personally use, love and can recommend to friends with complete confidence.

Comments 19

  1. Hi there, 1st timer, lol green green green, lol.. We’re heading moving from NC to Calif. Unfortunately didn’t get a trial trip in fist. Got a 2008 Jayco Designer and still figuring out everything, will be using your video on flushing hot water today, wish me luck. My question, What are some major points to look out for driving cross country? I’m a long haul truck driver by trade, so not too much will be a surprise for me. Lol. But I am a little nervous about finding fresh water dump stations etc.. Any pointers? Much appreciated. I’d also like to ad that I’ve found your videos to be the most informational and clear cut. Very easy to follow and understand, especially for the first timer. I feel like a green rider on a black stallion, lol…

    1. Post

      Congratulations on your new RV, Jennifer! Thanks for your great question and nice note. If you are a trucker, you will have NO problem out there! Driving is the biggest issue we’re asked about by new RVers, and you’ll find it easy as pie with your experience. As far as finding places to dump, check out for a pretty extensive list. They might not always have a source of potable water available though. If needed, you can also usually dump black & gray, and fill fresh at many RV parks for a fee (sometimes $5-$10). But you might decide to do what we do when we’re on the road for extended trips where we’re just covering a lot of ground…. stay in a full hook-up campground / RV park from time to time. We can comfortably and easily go a week without taking on fresh water or dumping (longer if we really need to). So we just make sure to stay overnight at a full hook-up at least once a week. We “refresh resources” that night by filling the fresh tank and dumping black & gray. We even get some laundry done, too. 😊 Safe travels and have fun out here!

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  3. First of all, thank you for all the great information you provide. I have a 04 Rockwood Roo 19 travel trailer. The draw tube for anti-freeze is on the suction side of the pump between the fresh water tank and the pump (I can see the lines). If bleach was drawn through it, the lines would get sanitized but not the tank. I would guess that many (maybe most) RV’s are designed this way. I think the best way to sanitize the cold water system is to place the bleach directly into the fresh water tank. To fill the tank by hand, I like to use a watering can (for gardens) with the sprinkler head removed by unscrewing.

    Thanks again,


    1. Post

      Hi Doug! Thanks so much for your comments. If you’re able to pour water (or bleach) directly into your fresh water tank, you have what’s called a “gravity fill,” which is basically just an opening through which you can pour water right down into the tank. So using the winterizing kit isn’t needed, even if it were plumbed to allow it. Our first RV (a Fleetwood Bounder) had the same thing.

      Our current RV has no gravity fill, so the only way to get water into the fresh tank is through the hose that connects the RV to city water. Some RVs that have only a city-water fill (no gravity fill) also have winterizing kits that are plumbed like yours, with no way to add water to the tank through the kit. Without that ability, and without a gravity fill, here is the trick for adding bleach to the tank:

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  5. Hi guys! With the Clorox they sell now that says concentrated I’m assuming 1/4 c for 30 gals? That should work OK. D&B in Tucson

    1. Post

      Hi D&B!

      Since the chlorine concentration level is what matters, you are indeed correct that the amount should be adjusted if you’re using concentrated bleach. Regular bleach is typically a 5.25% sodium hypochlorite solution, yielding a 5% available chlorine concentration. The concentrated stuff is typically 8.25% sodium hypochlorite, yielding 7.86% chlorine (double check your bottle to be sure). So reduce the amount of bleach accordingly.

      Assuming 5% for regular and 7.86% for concentrated, let’s drag out some high school algebra to work this out (hope we get this right… it’s been a LONG time!) lol

      0.05 / 15 gallons = 0.0786 / X gallons
      0.05 X = 1.179
      X = 1.179 ÷ 0.05 = 23.58

      If we got it right, you can use 1/4 cup of concentrated bleach for every 23.58 gallons instead of 15 gallons with the regular bleach. To ensure you end up with the minimum required concentration, we’d round down to 1/4 cup for every 23 gallons of tank capacity.

      Let the mathematicians out there correct our calculations as needed! lol

      1. WAY too much math for me, I used about 5/8c for 78 gals & called it good. This was just to kinda freshen the tank up a bit. Heading up to Cottonwood on Thursday, if that is still too hot we’ll keep heading N. Don & Bobbi

        1. Post

          Too much math for us too, but a fun exercise. Could you see the smoke rising from the tops of our heads? lol

          Cottonwood, as in Arizona? Don’t you & Bobbi know it’s summer!?!? LOL

          Stay cool down there. :)

  6. We are camping this weekend and the sulfur smell is back. I did as you recommended and flushed the water heater with vinegar, which seemed to do the job, but the smell is back. I watched the new video on sanitizing both the hot and the cold. Should I leave the water heater in the loop and sanitize it that way. What do you recommend.

    1. Hi Mark. Sorry to hear that vinegar didn’t solve your problem for good. We would definitely try bleaching the entire system, including the water heater. Follow the the directions we outlined in the video about sanitizing the entire water system (both hot and cold sides), but with two changes.

      First, empty your water heater (of course making sure it’s turned off first, and be careful not to burn yourself when draining it). Then leave the bypass valves in the normal use (not bypassed) position. Then you can follow the rest of the directions.

      This will bring bleach water from the fresh tank into the water heater. The reason you’ll be emptying the water heater first is to be sure that a strong enough concentration of bleach enters the tank. You will likely want to empty the heater again afterward to get as much bleach as possible out of it. If possible, leave the bleach in the entire system overnight or longer. Hope this helps, and again, please let us know how you make out.

  7. Not sure about the website but I need info about the rv tires. We have 2009 Coachman Freedlander class C. Has 16000 miles, not driven much & the tires looks good. Been told they need to be replace but the Lincoln penny’s head show very good, Its the black outer layer that is beginning to look a little rough. We should have had them covered. Some people have told us they should be replace if over 5 years old.
    What about the inside tire that you can’t see. Is there not some kind of coating that could be applied to protect it? I would appreciate any ifo that anyone could give me. Glo

    1. Hi Gloria. It’s far more common for RV tires to have to be replaced due to age long before mileage or wear. Because RVs are usually not driven as much as cars, the tread is usually very deep for a longer period of time, but that doesn’t change the fact that tires should be replaced after a certain amount of time.

      Here’s a video showing how to find the manufacture date of your tires. It’s a 4-digit code that’s part of the DOT stamp in the sidewall. The last 4 digits are in an oval, showing the week and year of manufacture. For example, a 3810 in the oval would mean that the tires were manufactured during the 38th week of 2010. Here’s the video:

      It used to be that 5, 6 or 7 years was considered the maximum age a tire should be used. It’s more often now that 10 years is considered the maximum, depending on manufacturer. There is also a caveat with that: beginning at year 5, they should be inspected annually, and if the condition warrants it (such as sidewall cracking) they should be replaced before 10 years. Our RV’s tires are now 9 years old, and in great shape. We keep them covered a lot of the time when parked, and have them inspected annually. Since they show very little sign of sidewall cracking, we’re on target to get the full 10 years out of them, and we’re planning to replace them all next year.

      We keep them clean, which is important for keeping them in good shape. After washing, we treat the sidewalls with Aerospace 303 to protect them from UV and moisturize the rubber. Nothing you can do about the parts of the tire you can’t see, but they’re the most protected from the sun, so the outer walls (the visible part) will generally age first anyway.

      Based on what you’ve said, we recommend having them inspected immediately by a tire professional and let them make a recommendation. Of course an unscrupulous tire store will tell you to replace them no matter what, so go to someone you can trust.

      Hope this helps!

  8. What if you can’t take the trailer for a drive? My trailer is my year round living quarters. It doesn’t go anywhere. What do you suggest?

    1. Hi Jennifer. Taking the RV for a drive to agitate the bleach is nice to be able to do, but not essential. If your trailer never moves, you’ll still be okay if you follow all the other steps.

  9. How do you recommend getting rid of the sulfur smell from the hot water tank. Can this be done by putting the bleach thru the hot water tank instead of bypassing it.

    1. Hi Mark. Your best bet is to flush the water heater. We have two videos about that (one focusing on Atwood heaters and one for Suburban heaters), plus an important follow-up video about Suburban anode rods. You can find the links below.
      Suburban follow-up:

      Hope this helps. If flushing your heater with vinegar still leaves a smell, there is no harm in then trying bleach. Use the same 1/4 cup of bleach to 15-gallons of water ratio as for sanitizing the fresh water system. But we’re thinking that a proper vinegar flushing of the tank should help a lot, and maybe solve the problem altogether. Best of luck and please let us know how you make out.

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