Hard Water? Try the Vinegar Trick

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 affects 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, 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 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. 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.

Photo: Telltale signs of hard water where hot water pressure valve "wept" minerals.