Wednesday, May 04, 2011

WFMW: How to get rid of hard water stains

Do you have hard water at your house?  Stains that you just can't get rid of?  Vinegar is your friend.  Let me tell you how.

We have hard water in our house.  Very hard water.  This was our sink before we replaced it.
That was after lots of scrubbing, with a wire brush, soft scrub with bleach, etc.  You can't really see it, but there was actually a couple millimeters of built up calcifications.  Needless to say?  Gross!

My bathtub wasn't quite as bad, but where the water pooled in the bottom there was a definite ring and I just never felt like I could get it clean.

Then somewhere online I stumbled upon the answer.  Common household white vinegar.  (If this is you? Buy it in bulk at Costco!)  I already had plenty on hand because we use it as a water softener and stink remover with our cloth diapers.

The directions said to put a cup of vinegar in a toilet bowl to get hard water stains out.  So I figured 2 cups in a couple inches of water in the bottom of my tub should work.  I let it stand overnight and in the morning...

You might have to click to really see it

Great, now you can see the line!  I had a pretty clean tub bottom, but the rest of it now looked grungy.  So I did it again with about 4 inches of water (and attacked the stain in the hand hold area too).  The bottom was getting cleaner, but... new line.

So Monday I filled the tub up as full as it would allow and just dumped in about half a gallon of vinegar.  I went back every hour or so and rinsed the walls above the water line as well.  Now?

I don't feel bad about letting guests take a shower in my bathroom! (And while it still sort of looks like there's a line in these pictures I think it has more to do with the curve of the tub.)

And I didn't actually believe it would all come out of the tub bottom, but after 3 soaks there's absolutely no discoloration left!

The best part about this???  Completely non-toxic!  I didn't feel bad about rinsing the tub a little and then sticking my boys right in for a bath.

And now for the really geeky part... how do you know your vinegar is working?  You'll see little bubbles on the surfaces where the reaction is taking place.  Sweet, a chemistry reaction in my bathtub!  See vinegar is a weak acid (CH3COOH) and all these buildups are bases, usually calcium carbonate (CaCO3).  The acid is actually dissolving the calcium carbonate and the bubbles you get are carbon dioxide.  You can see the reaction here.

So, if you have hard water, try it!  I also soaked my shower head in a bucket because I forgot to just put it in the tub when it was full.  Now, a shower that doesn't spray off in wonky directions!

What works for you today?

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  1. Great tip. Fiberglass tubs are so difficult to clean.

  2. Hi! Visiting from WATF. Great tip! I'm curious, what is your cloth diaper washing process? I am battling hard water stink & stripping just isn't enough...

  3. It works wonderfully on the scale built up on the inside of your electric tea kettle too.

    I tend to alternate vinegar and Scrubbing Bubbles on my tub since they take off different things and are both very easy. I've just taken an empty spray bottle and filled it with diluted vinegar and use it like any standard spray cleaner.

  4. we had a nasty chemical reaction with a cleaner I bought a few months ago. It was some kind of Oxi-type cleaner and when sprayed on the buildup it made some pretty nasty fumes... needless to say I threw that bottle out! I'll have to try the vinegar as I haven't been too diligent about scrubbing my tub lately. It's getting hard to bend over and scrub (and to try to get back up off the floor!) :)


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