Tuesday, October 3, 2023


Curing the curse of hard water RV plumbing issues

By Russ and Tiña De Maris
For folks who live up in the Pacific Northwest, the curse of “hard water” probably never enters your vocabulary. It never did for us – until we started spending time in the Desert Southwest. We quickly learned how much trouble a few “mineral deposits” in the water supply can create. Deposits in pipes, fittings chewed up, a whole host of plumbing nightmares.

There is a way that can help you counteract the negative aspects of hard water. Some swear by “the vinegar treatment.” Once a year, so say the resident experts, pump a solution of white vinegar and water into the RV water system, allow to stand overnight and dissolve hard water deposits. The dilution rate usually is set at 1:1 white vinegar to water.

Phase 1 to clean out mineral deposits from water system

Want to try it? First, turn off your “city water” supply and the power or gas to your water heater. Drain your hot water tank, and reclose 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.

Phase 2

You’ll need plenty of white vinegar. We 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!

Phase 3 to clean out mineral deposits

Back home, turn on the water pump. Open your valves, one at a time, and let the water flow until you smell that good old 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. Again, allow the solution to “sit” for several hours – overnight or even longer if you can.

Phase 4

To make things work even better, use a water heater “flush wand” that pokes up into the water tank through the drain valve. Whoosh it out good to remove as much scale as you can, then close the drain. Do this trick before you turn on the water pump to fill up the system with the vinegar and water solution. Some have commented that vinegar may chew up the anode rod. Combining acetic acid with magnesium (the principal component of an anode rod) does produce magnesium acetate – and it makes for an interesting science experiment. However, rather strong acetic acid (35 percent) is required. By the time you dilute the already low-acid (5 to 8 percent) vinegar with water, our thinking is, sitting around in that weak solution for 24 hours or so isn’t going to chew up your anode rod. If you’re worried, pull out the anode rod and put in a plug. You may find that it’s high time to replace the anode rod anyway!

After your “stand time” clock has run its course, 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.


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Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.


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1 year ago

Why not just buy a water softener? Simple solution to a very expensive problem if left unchecked……

Phil & Peggy
1 year ago

We had this problem when we first moved to Tucson years ago. And your RV plumbing is only one of the victims — after our first year there the doctor told me that we were in the kidney stone capital of the country due to the hard water.

Our solution was to install an RO system which cleaned up the water so well that the RO water cleaned out all the deposits by itself and has kept the entire system RO clean ever since. No more bottled water, no chemical cleansing, no more water issues, even in Yuma (worse than Tucson) where they have clean water stations throughout the area that we do not have to patronize.

1 year ago

Don’t forget your appliances like the Mr. Coffee or similar devices. They have an in-line high temp. detector which gets crusted up and breaks the circuit. It is too expensive to fix – so replace the appliance!

About every 90 days – I put in a clean filter, about 6 cups of 100% white vinegar, percolate it out into the coffee pot below – let the heater cool, then fill with fresh water, percolating it out. (Pour the used vinegar back in the bottle for future use). The results will be seen in the filter and your appliance will last many years!

1 year ago

Your water heater instructions are for the old fashioned tank heaters!
What are the instructions for the instant hot heaters?

Tommy Molnar
1 year ago

While down in Houston for eight months we experienced really bad hard water. We talked with several other occupants of the RV park we were staying in and they recommended a portable water softener. We got one, and it made a HUGE difference. Once we got as much of that white crud out of our toilet flush, and the faucets in our sinks, life got good (water-wise anyway). We liked the results SO much we had a water softener installed in our house back in NV when we got home.

Last edited 1 year ago by Tommy Molnar
1 year ago
Reply to  Tommy Molnar

I second the portable softener. I’ve been using one for years. I always test before hooking up or filling. If hard water, the softener comes out.

1 year ago
Reply to  Tommy Molnar

I think the water softener is a much better idea than going though the process described here.

1 year ago
Reply to  Tommy Molnar

I’ll third the vote for a portable water softener. Nice having a more consistent water chemistry whereever we travel.

David J
1 year ago

A citric acid solution is just as effective as vinegar. Plus, it doesn’t leave a nasty aftertaste behind!

1 year ago
Reply to  David J

David, what type of citric acid do you use?

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