Testing for Water Hardness (Video)

Check out my 2018 update of this video, with far better sound quality: Using Soap to Test for Hard Water.

The term “hard water” refers to the concentration of minerals dissolved in the water. “Soft water” indicates that there are very few minerals in the water. In this video, I demonstrate how to test for it in your water supply. You can then use this information as a tool to diagnose issues around your house, such as why soaps don’t rinse as easily, why you have soap scum, why there’s build up of mineral deposits inside faucets, and why you may have lower water pressure due to build up in pipes. Keep in mind, from my soap scum blog, that acids (like vinegar) dissolve water deposits.

24 thoughts on “Testing for Water Hardness (Video)

  1. hi

    i’m considering switching to the castile soaps but like a lot of y’all I have hard water. my question is, can I use something besides vinegar for the laundry rinse? I just don’t want to smell like vinegar, especially when it’s hot out!


    • Hi KatD – The vinegar smell totally dissipates once the laundry is dry.

    • Been using vinegar for years on my bath towels and kitchen towels. Didn’t make sense to use a fabric softener, that repels moisture, on items that were needed for absorbing moisture. The vinegar dissipates, leaving behind no smell. Usually line dry(sun kissed), and fluff in the dryer, except in the winter. Can add a few drops of essential oil to wool balls for dryer use. I highly recommend http://1840farm.com/2016/02/1840-farmhouse-home-handmade-100-wool-dryer-balls/

  2. We have very hard water here, and when using the castile soap my hair broke off, almost a foot in length, due to hard water buildup. Organic shampoos were no better. I am wondering how the Sal Suds would work for removing the mineral buildup on hair.

    • I very mild vinegar solution will dissolve the calcium deposits.

  3. Thank You! I have been scouring the internet for two days for this information and just stumbled across your website – knowledgable information right from the source!! I clean houses for a living and recently, due to bronchial damage from bleach exposure, became unable to use commercial cleaning supplies. Even “green” cleaners cause my airway to swell. So I found a recipe for a baking soda paste (using Dr. Bronner’s castile soap) online that worked AMAZING on soap scum. But the next time I used it on that same tub, I saw that it was leaving a residue behind. I was so bummed that I couldn’t use my new cleaner anymore. When looking for homemade cleaners, the recipes usually call for “distilled” water, but I always used tap because it’s right on hand. Now I know why it is so important!

  4. RO water has NO minerals left. Distilled will also be devoid of any minerals. The RO process dumps at least 4 gallons of water for every one made. We have very hard water. Calcium carbonate is the culprit for many of us. Water softening does not eliminate it, it adds salts. Some cities are beginning to ban water softeners because of the expense to the water authority to remove all the salts dumped into the waste water. Vinegar is simply the best and cheapest acid to mitigate calcium deposits. Try some vinegar in the water to lower the pH and see if that helps with suds. Seems to work here with heavy limestone (calcium) deposits.

  5. I just did this test except I used three samples; one was tap water (very hard), another was water out of my RO system and the last was bottled (purified) drinking water (from filtered and RO process – they do add some minerals back for taste such as calcium chloride and sodium bicarbonate). The one that did the best was the RO water from my system which makes sense since there are fewer minerals than the bottled water. I am going to repeat this test with distilled water to see the results.

  6. Hi Erica – To reduce the hard water issue when washing dishes, avoid using a sink full of water and adding the castile soap. The soap will immediately react with all those minerals, and will be much reduced before you have a chance to do any washing. Instead, put all the dishes in an empty sink and run water over them just to get them wet. Put a small squirt of soap on your wet dish brush or washcloth. (I prefer the brush.) Wash all the dishes with that, then rinse them. Also, hand drying the dishes will cut down on residue as well, although you may not need to at this point. Let me know how it goes!

    All the best,

    • Hi Lisa,

      Do you recommend diluting the soap at all when using this method?

    • Hi Jo- No, just a small squirt of Castile Soap, straight from the bottle.

  7. I’m wondering if there is anything I can do for washing dishes if I have hard water? It just turns cloudy and no suds. 🙁 I’m moving in a couple months, so I don’t want to buy a water softner. I just bought this soap for te first time. We want to use it for every day cleaning, washing dishes, shampoo, and body wash. Any tips to make it work for us?

  8. Hi Mary – If you’re using a washcloth, let the water already on the wash be your dilution. Just add a small squirt of the pure soap to it. If you’re pre-diluting it, and then adding it to a wet washcloth, you’re kind of diluting it twice.

    Let me know what you think of the other methods when you have a chance to try them.

    All the best,

  9. Thanks for all your tips. I am just now getting back here to read them. The scum in the shower is from when I use it as body wash and shampoo. I dilute the soap a lot (it’s probably less than a 1:4 ratio, but i just eyeball it so I don’t know exactly) before I use it because it seems so strong, but then because it’s so runny, it tends to get everywhere. I’ll try the 50/50 vinegar spray for the dishes and the shower / tub. When I put it on the washcloth it seems like there’s none left to get on my skin to make it clean which is why I tend to use it directly in my hands. although I realize this is probably more perception than reality.

    I might try sal suds for dishes but I’ll try the vinegar spray idea first. Thanks again!

  10. I just switched to Bronner’s soap a month or so ago but I’m having some issues with it. After watching this video I realize that part of my problem must be that I have very hard water (the soap instantly makes lots of white clouds in the water), but I’m not entirely sure what to do about it.

    I saw your post about how to help fight “soap scum,” but I hate that I have to clean my bathtub every few days or else it just gets really nasty. I’m also pregnant and in another month or two kneeling down to scrub the tub will not really be a very workable solution (although it might be a comical one).

    It also leaves residue on my dishes. I tried adding vinegar to my rinse sink but it didn’t seem to help at all with the residue. The residue on the dishes really isn’t that bad, but it bothers me on my glasses.

    Any tips? I’d really like to keep using this soap because I know that it doesn’t have all the bad stuff in it which many conventional products do, but I’m about to switch back because of all the extra work I have to do to fight the residue / scum.

    • Hi Mary – Are you using the castile soap on your body, or as a bathroom cleaner? It works for both, but my tips for you are rather “use dependent”. If the scum is resulting from your using the product on your body, make sure you’re not using too much of the soap. Use a washcloth so that very little soap hits the tub/shower surfaces without being used. Squirt about 1/2 Tbsp. on the wet washcloth. That should be enough for your whole body. For hair, use just enough soap. I have long hair and use about 1/2 Tbsp. Also, regularly spray down your shower with a vinegar solution (about half and half with water). You don’t have to wipe this off. Rinse the tub with a cup of water. I totally understand the pregnancy constraints – once you’re down, it’s very hard to get back up – been there three times myself. Spray bottles come in very handy during this time. You also might want to get a tub-exclusive mop, that you can use to wipe down the surfaces without having to get down there yourself. I like the microfiber ones that screw on to the handle – you can just toss them in the washer to clean them.

      For the dishes – would you consider trying the Dr. Bronner’s Sal Suds? You will not have the scum issue. However, if you’d like to stick with the organic castile soap, use a vinegar spray (same as the tub) and spray your glasses with the vinegar. The 50% solution is needed, so unless you want to fill your sink with half vinegar, the spray bottle might be more efficient. Put all your wet, washed glasses in the sink, and spray them all at once. Then, rinse over them with running water.

      Let me know how these are working for you. I’ll keep thinking of more options.

      Super-big congratulations on your baby!

      All the best,

    • I bought a nice scrubber on a long handle. I’m old and disabled and that works for me. Every couple of days a mild solution of vinegar breaks the calcium deposits up. Vinegar is the best and mildest acid solution for household use. Full strength it removes hard white calcium deposits. Usually that’s the problem in hard water.

  11. Amazing. Now I have a question regarding mixing castile soap and hard water for the homemade cleaners. Is it alright to mix hard water or should I be using distilled water to make my cleaning products with castile? I’m only asking because I am finding the white film on some of my surfaces. And yes I know about the vinegar rinse, but I was wondering that by using distilled water, would be better in general? Thank you.

    • @Noemi – Using distilled water in your solutions would definitely eliminate the cloudy water and the soap scum.

      All the best,

    • Agree. Thanks a bunch. I love Dr Bonner’s products & philosophies!

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