Friday, December 9, 2022


Hard water hard on RV plumbing? Try vinegar!


By Russ and Tiña De Maris

photo: _gee_ on

Having spent a number of years in the “naturally soft water” country of the Pacific Northwest, it was a shock to us when we learned about the effects of hard water on RV plumbing. In the last few months we’ve helped out with a number of RV plumbing failures in the Southwest, all related to hard water. Seems like the stuff makes deposits inside pipes, and can even eat through fittings.

Some swear by “the vinegar treatment.” Once a year, it is said, a solution of white vinegar and water should be pumped through the RV water system, allowed to sit and dissolve hard water deposits. We haven’t tried it yet, so if you’d like to be an RV Guinea Pig, let us know how it works.

First, turn off your “city water” supply and the power or gas to your hot water heater. Drain your hot water tank, and re-close the drain fitting. Next, if there’s water in your fresh water holding tank, drain it out. Now turn on the RV water pump. Open all your water flowing fixtures and run them until air spurts out. Turn off the fixtures and water pump, and you’re ready for Phase 2.

You’ll need plenty of white vinegar. We’d recommend dumping about 4 gallons of the stuff into your fresh water tank, along with an equal amount of fresh water. If you can, drive your rig “around the block” to swish the solution around in the fresh water tank. Of course, you took the time to close the fresh tank drain valve before pouring in the vinegar!

Back home, turn on the water pump. Open your valves, one at a time, and let the water flow until you smell that good ol’ strong vinegar odor. Close the valve, and repeat with all the fixtures in your rig. You’ll also be doing the “hot” side too, so your hot water tank will fill with this same solution. Allow the solution to “sit” for several hours — overnight would be good, if you can.

Afterwards, drain your fresh water holding tank and hot water tank. Refill the fresh tank with fresh water, and thoroughly run all fixtures until the odor and any color is gone. You may need to do this several times to get all the hard water minerals out of the system.

##RVT795 ##RVDT1326

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2 years ago

I know that, this method works just fine for cleaning out Coffee pots. I do this about once every month to my electric coffee pot. I mix the Vinegar and water 1/2 water & 1/2 vinegar and then turn it on to let it brew just like I’m brewing coffee. Then after it finishes brewing I pour the mixture out, and then do the same brewing method 4 more times with nothing but just plain water to remove the vinegar residue. – Works every time. I started that process one time after my coffee pot got so plugged up with hard-water minerals that it almost quit working totally. Somebody else told me about that method when I told them I needed to buy another coffee pot. Well, They were right, it worked, and I still use that method to this very day. – Many Thanks to the ones that told me about this method years ago.

Patricia Panuccio
2 years ago

That is a lot of water being wasted. Using filters inside and outside the rig might be better for the environment especially out west where water is like gold.

2 years ago

That’s why I test the water for hardness wherever I am before hooking up or filling. If needed I use my portable On The Go softener. Makes a world of difference and I will never have these problems.

Bob Godfrey
2 years ago

Would you have to remove water filters before doing this?

2 years ago
Reply to  Bob Godfrey

Yes, I always do

2 years ago

Remove the screens from faucets or the chunks will clog them up

5 years ago

What if you are a full-timer? It would be hard to do the overnight soak.

Tommy Molnar
5 years ago

I’m not sure our on-board water system would operate with only four gallons of liquid in it. We’ve had priming issues before when we had only a small amount of water on board.

2 years ago
Reply to  Tommy Molnar

I always put in a lot more than that. Water heaters are 6 or 10 gallons themselves. I usually use 6 gallons of vinegar and put in about 10-15 gallons of water. Have done this for over 20 years and never had an issue on any of my 4 campers.