The Hard Water Headache

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Dear Home-Ec 101,
I was visiting my MIL recently, and she told me that they have hard water, so she had to put a lot of extra soap in the washer because otherwise, she didn’t get any bubbles, and it wouldn’t clean the laundry. This confuses me because I always thought you weren’t supposed to have a lot of foam in the washer. I’ve read articles recently saying that most people use way too much laundry detergent. Also, the man who installed our new septic system told me that I should use liquid soaps because they didn’t foam, and foam would not build up in the septic system (which is apparently a bad thing).

I suspect that my MIL simply doesn’t know what she’s talking about, but I would never say so to her. If I’m wrong, please correct me- or at least just clear this up so I can think about something else!
Biting My Tongue

hard water and washing clothes

You are both partly right.

Laundry detergent isn’t just one thing; it is a blend of ingredients in either a solution or powdered form. Some of it is soap, some detergent, some surfactants, and water conditioners, and then we get to the perfumes and dyes.

Hard water is water that has calcium and magnesium in the solution, and these dissolved minerals cause a lot of headaches in your laundry. If they are not suspended in water when the wash water or rinse water is drained, the magnesium and calcium can cling to clothing, causing fabrics to feel stiff and dulling the color. Think of it a bit like looking through a slightly dirty window; usually, you can’t focus on the dirt, but your view of the outside world isn’t as bright and clear due to the slight film obscuring the view.

It is often necessary to use more laundry detergent in hard water.

When laundry detergent is added to hard water, a number of the detergent molecules — which I’ve been describing ad nauseum of late — get used up binding the calcium and magnesium. This simply means that in all conditions being equal, there will be fewer detergent molecules able to trap dirt in hard water than in soft water. Soap molecules that come in contact with minerals form our nemesis soap scum which is difficult to remove from wherever it decides to cling.

Please do not expect Home-Ec 101 to help you study for your physical chemistry final, I am only trying to get across basic concepts.

In chemistry, we often talk about something called the saturation point. When something is saturated, it can’t hold anymore. In your laundry, this is the point at which no more detergent can be in the wash water. Whatever cannot be in the water falls out as precipitate. (Remember it like this, when it rains, it’s precipitating — the cloud cannot hold any more moisture, so it falls out of the sky.)

Water can only hold so much soap, even if that detergent is busy holding minerals like calcium and magnesium in solution -the clusters of soap around oil or dirt are called micelles. So there is a point at which too much of anything is going to precipitate out of solution. Where that precipitate (dirt, oil, gunk micelles) goes depends on its density, it may sink or float on top of the water in a scummy layer.

As consumers, we tend to associate soap suds with laundry detergent doing its job.

Foaming and bubbles occur when the air in your washer agitates, splashing the water around and trapping air. Bubbles and foam are actually two layers of soap sandwiching a tiny film of water. Air gets trapped in this film, creating bubbles; as more air is introduced through splashing, you create the foam and suds we are all familiar with.

For the most part, suds aren’t coming in contact with the clothing, and when the water drains, the suds leave a sticky film of soap behind. If there isn’t enough rinse water to bring everything into solution, those deposits will stay on the fabric, which pretty much defeats the entire purpose of doing laundry.

People who live in areas with hard water do have a few tools at their disposal. 

Heat improves solubility.

Cold WaterWarm WaterHot Water
65°F – 75°F80°F – 105°F120°F – 140°F
18°C – 24°C27°C – 40°C49°C – 60°C

In general, higher temperatures allow more soap or detergent to be in the water at a given time.

Additionally, please note that most laundry detergents aren’t going to be very effective at temperatures below 60°F or 16°C. If this is the only option, try dissolving powdered detergent in a small amount of hot water before adding it to the washing machine. This will help prevent those white powdery streaks caused by undissolved detergents.

Water conditioning

Those looking to improve the effectiveness of their laundry detergent in hard water can give conditioning their water a try. Water conditioning is the process of getting the calcium and magnesium out of the water where it won’t use up the detergent. This is typically done by exchanging the calcium and magnesium ions with those in salt (sodium and chloride). Now keep in mind that some laundry detergents already contain ingredients, known as zeolites, that condition the water.

Point of Use Water Conditioning

If you want to soften your hard water only in the clothes washer, be sure to purchase a non-precipitating water softener. Non-precipitating water softeners work best when added to the water before the detergent; this prevents the detergent from beating the water softener to those pesky ions. Yes, this means you will have to be more attentive to your washing machine when doing laundry.

Precipitating water softeners will cause the minerals to fall out of solution where they will likely cling to clothing and the inside of your washing machine, completely defeating the purpose.

Whole House Water Softening

Water Softener

Water softeners are a fairly common solution that also works by switching out the calcium and magnesium with the ions in salt by passing the water through a chamber of resin beads. These beads have to be recharged with salt on a regular basis. There are some environmental concerns with choosing to use a water softening unit, and you should do your research thoroughly before making the investment.

Do not waste your time with a magnetic water softener.

You are not going to get the results you desire by slapping a couple of magnets around a pipe. It’s a scam.

So for the TL/DR crowd to answer your initial questions:

  1. Yes, you need more laundry detergent in places with hard water.
  2. Soap suds are not an indication of how well laundry detergent is working, and they can leave dirt behind.

Regarding Septic Systems:

Everything you allow to go down the drain affects the chemistry and bacterial balance of your septic system. Your septic system is designed to handle some variations, but if you go too far, you’ll upset the natural balance and end up with big problems.

Use the least amount of low foaming soap possible. The low foaming is critical for septic systems with an aeration chamber. As stated above, suds form when air is introduced to that soap film. Suds will leave behind soap and eventually clog the system.

laundry tips and tricks
Click the picture for more tips!

And those of you who have septic tanks should remember that it is better to spread laundry out over the course of a week than overload your system and upset the chemical / biological balance with a marathon laundry day. If you’re that far behind and the mountain of laundry is threatening to avalanche, consider saving yourself expensive septic repairs with the relatively cheaper laundromat option.

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18 thoughts on “The Hard Water Headache”

  1. @stevejberry I majored in biochem, it’s all in there somewhere, even if it gets a bit jumbled from time to time. This isn’t how I planned on using my education, but life is funny. I’m still not sure it was worth the student loans, either.

  2. @HeatherSolos @stevejberry Hey at least it sounds impressive. Try telling someone you majored in religious studies. *crickets*

  3. If you really want to ‘see’ bubbles, use non-HE detergent in a HE washer. Not recommended unless you want a big mess.

    My parents recently installed a HE washer/dryer in an upstairs closet for guests. Her aunt came to visit and used her own laundry detergent, needless to say there was much bubble overflow. My mom didn’t realize that her detergent wasn’t used so she thought there was an issue with the machine. Repairguy came out, couldn’t move the machine by himself. CAme out 2nd time with 2 guys took the whole washer apart couldn’t find anything wrong. Mom finally realized that the wrong detergent had been used.

    Long story short, if you are doing laundry at somoene else’s house, either use their detergent or ask first.

  4. @bookchick I’ll see your crickets and raise you a hoot owl. That’s still more impressive than a Piled Higher and Deeper from the School of Hard Knocks. 😉 I am a legally ordained clergyperson, but don’t have a divinity degree. You don’t need one in Texas. FTR, I was a math and physics major before I ran out of money XX years ago, and I spent slightly less than XX years as a technical writer, so Heather speaks my language when she gets technical. Grrrrrrrrrrrrrrrl geeks rule! (And student loans are a freakin’ racket.)

    Now what was I really going to comment on? Oh, yes, Borax. Wonderful stuff if you have hard water, particularly if you want to use less detergent or remove detergent buildup. Vinegar, too, but it can leave a weird residue sometimes because all that detergent/mineral goo can trap lipids (oils and fats) that are released when the vinegar dissolves the mineral.

    The more I hear about HE machines, the more negatively impressed I am.

  5. @KeterMagick I like mine and I even liked it when I was cloth diapering. That said it has its quirks that probably would make it too annoying for others and I seriously need to replace the big rubber gasket that has an annoying tear.

  6. @HeatherSolos And since it was on the 2nd floor it wasn’t noticed right away – at least the floor was really clean.
    This is the same aunt who uses her corningware bakeware as a skillet on the stove, I’m just waiting for it to explode one day. She’s slowly edging closer to the move in with a kid stage unfortunately, but she will be 90 in a month so that’s still pretty impressive.

  7. Thanks you so much for this- it has been exceptionally helpful. A follow-up question…

    I have started making my own detergent (borax, bar soap and washing powder recipe) and I was wondering if there is a way to make that more effective in my hard water. Should I be using a particular kind of bar soap? I have a septic tank, so i use liquid detergent, and frequently have to use an additive in my dishwasher to get my dishes clean, but there doesn’t seem to be an equivalent for laundry.

  8. @bookchick@HeatherSolos@stevejberry i’ve found telling people you’re a physicist usually makes for a pretty short conversation with most people

  9. Thank you for explaining it so well heather!! I use cloth diapers and have had so many head aches trying to figure out how to safely wash my diapers in my VERY hard water. On the one hand I don’t want to use too much soap, because film on a diaper makes it no absorb pee….but on the other hand not using enough soap means the pee isn’t cleaned out fully and PEE YEW the stink! This post helped me understand that using hotter water will help me, thank you!

  10. We use cold water frequently when doing laundry to save on electric bills. I’ll give warm water a try that I’ve learned this info. What soaps do you recommend for showering with hard water?

    • Connie,

      When ever I visit family who has hard water I all ways use dove bar soap. For some reason it seems to work for me. A lot of people also recommend Ivory soap.

      • I have hard water. My husband uses Dove bar soap and I use Aveeno liquid soap. Both suds up nicely. In my HE washer, I use Tide HD liquid detergent. Unless the clothes are extremely dirty or stained, I fill the detergent dispenser to the minimum line. Plus, I only use about a tablespoon of fabric softener. I wash my colors on warm/cold and my whites on hot/cold.

  11. Just wondering if having hard water could be the reason it takes my laundry so long to dry. I had both washer and dryer serviced and put new belt on washer. still is taking forever to dry. Just wondering if clothes take longer to dry when washed in hard water.?????

  12. I grew up with hard water and using a wringer washing machine. We always referred to doing laundry as rehearsal for pickling season. The laundry went from the wringer to a first rinse in the first laundry tub filled with cool water and 1 cup white vinegar. Then another pass through the wringer in to clear cold water. No residues ever, and the fabrics remained soft. (We would reuse the second rinse for all the day’s laundry – unless there was more than three loads, then it was changed half way through the process. There was so little to be rinsed out except vinegar in the second rinse to do otherwise was wasteful.)

    If you have a difficult time getting your clothes to rinse clean after the wash cycle, buy yourself a gallon jug of distilled white vinegar. While the washer is filling for the rinse cycle, add 1 cup of vinegar to the wash. This creates what is called a redox reaction. (Detergent molecules & that to which they are bound are basic, vinegar is acidic. When they are mixed together, they create minerals salts and water. The mineral salts are then drained away with the spin cycle.) Do not add commercial fabric softener with the vinegar. You can end up with a gummy mess. The clothes may smell faintly of vinegar, but this should go away with the heat of the dryer. If you wish, just run the load through a 2nd rinse cycle with or without a commercial fabric softener.

    All my adult life, I have never been without a gallon of distilled white vinegar. There are just so darn many good things you can do with it!


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