Laundry Booster for Hard Water

SKU: 51700-P
In Stock
4.86 out of 5 based on 7 customer ratings
(7 customer reviews )

Charlie’s Soap Biodegradable Booster & Hard Water Treatment boosts your laundry detergent’s cleaning ability to give your laundry a deeper clean by controlling hard water and removing the build-up it leaves behind on your clothes and in your washing machine.

Share this Product


$18.99$113.94 or subscribe and save up to 5%


Hard water minerals like calcium and magnesium leave a residue on your clothes, making fabrics look dull and feel rough to the touch. It can also cause “scale” (also known as “limescale”) or mineral buildup in pipes and plumbing fixtures, reducing the effectiveness of both your laundry detergent and your washer.

Charlie’s Soap Booster & Hard Water Treatment is a biodegradable phosphate that eliminates problems associated with hard water and aids with natural biodegradation of compounds in nature. By controlling hard water conditions, our Booster lets you get the bright, clean, softer, odor-free laundry you love, without the damaging residue.

Charlie’s Soap Natural Booster & Hard Water Treatment Features

  • Fragrance-free
  • Works in both traditional top-loading washers and HE machines
  • Powerfully removes the effects of hard water, but is still gentle on sensitive skin
  • Safe for all septic systems
  • Effective in hot water and cold water cycles

Charlie’s Soap Natural Booster & Hard Water Treatment Benefits

  • Enjoy clothes longer. The effects of hard water residues can weaken your fabrics’ fibers, shortening their lifespan. Our Booster & Hard Water Treatment cleans your clothes without the mineral buildup, meaning you can enjoy them longer. 
  • Environmentally friendly. Our biodegradable booster is made from an environmentally safe phosphate that softens water and leaves no hard water scale.
  • Sensitive skin friendly. Rinses completely from fabric, leaving behind no additives or residue on your clothes that can irritate sensitive skin. One of our most popular uses is for cloth diapers.
  • Save Money. Skip the expensive water softening system, but still gain softer clothes with an affordable, all-natural laundry soap. Both your washer and your skin will thank you.  Our 2.64 lbs bag can treat up to 160 loads of laundry.  Compare that to other water softeners that only treat a few loads.

How to Use Charlie’s Soap Natural Booster & Hard Water Treatment

If you have hard water issues, use at least ½ tbsp of Charlie’s Soap Natural Booster & Hard Water Treatment per wash, pouring directly into the drum. Use 1 full tbsp for tough stains or excessively hard water. Works most effectively when combined with the cleaning power of our Natural Liquid Laundry Detergent or our Natural Powder Detergent. We recommend using hot water during your cycle, so that the water temperature allows the products to fully dissolve and work their magic.

It can take several wash cycles to remove the initial hard water build up in your clothes, but after just a few laundry days, you’ll see your laundry detergent work harder with noticeably brighter, softer, and exceptionally clean clothes, without the need for bleach, brighteners, or fabric softeners.

This hard water treatment product is eco-friendly and safe to use in all washing machines, including traditional, top loaders and high-efficiency front loading washing machines.

The Charlie’s Soap Difference

All of Charlie’s Soap laundry products are scientifically formulated to give you a deep clean with minimal impact on your appliances, health, skin, and the environment. All of our cleaning products are biodegradable, dye-free, hypoallergenic, and perfume-free

We believe that you shouldn’t have to sacrifice deep clean when you live green. For over 40 years, we’ve offered the best laundry detergents, stain removers, and water treatments, so households can enjoy cleaner, brighter laundry that’s gentle on the skin, all while extending the lifespan of fabrics and appliances. We’re proud to do our part in lengthening product and clothing life cycles, helping to keep them out of landfills. 

Ingredients in Charlie’s Soap Laundry Booster for Hard Water

Potassium diphosphate (7320-34-5) [water softener]

Ingredients You Won’t Find in Charlie’s Soap Products

  • Baking soda
  • Zeolites
  • Fragrances
  • Bleach
  • Anti-foaming agents
  • Essential oils
  • Thickening agents
  • Enzymes 
  • Dyes
  • Odor blockers
  • Preservatives


Use at least 1/2 tbsp. of Charlie’s Soap Booster as needed per wash.  Use 1 full tbsp. for tough stains or excessively hard water.  You may apply Booster directly to the drum.  Wash according to care instructions.  Test on garments that may bleed for fade.

Charlie’s Soap Booster and Hard Water Treatment uses a simple phosphate that:

  • Softens your wash water.
  • Allows Charlie’s Soap detergent to work better in the wash.
  • Rinses completely leaving no residue on your clothes.
  • Aids in natural biodegradation in the environment, when using 1 tbsp. per wash.
  • Keeps your clothes and the environment clean.

Customer Questions

Is this just a booster or is it also laundry soap? Should it be used with laundry soap or just alone?

Our Booster/Hard Water Treatment was designed to be a companion to our laundry detergents to help customers that find themselves in need of additional cleaning power.

Hard water can be a combination of many different mineral types depending on where you live, time of year, or climate and can vary vastly. Our detergent does such a good job of removing dirt and contaminants that it sees those minerals as “dirt” and will latch on them to remove them from the wash water as well.  Depending on how many minerals there are, it may make it harder for Charlie’s to grab the dirt along with those minerals, and you may see your laundry not bright or possibly stiff from the deposit of those extra minerals back onto your laundry.

Using Booster/Hard Water Treatment helps rid the wash water of those extra minerals, allowing the detergent to concentrate only on the dirt and stains.

Customers' review

Rated 4.86 out of 5 stars
7 reviews
5 stars 6 85 %
4 stars 1 14 %
3 stars 0 0 %
2 stars 0 0 %
1 star 0 0 %

7 reviews for Laundry Booster for Hard Water

  1. 4 out of 5

    Pleased I found out about this product from my daughter. I live in a part of the country that has very hard water. Since I have a well I was curious about this product. I have a front-load washer and hard water is a problem with getting clean laundry. I have been very impressed with this product. It has allowed my detergent to work better and get the clothes cleaner. I am hoping that after time it will also help to eliminate hard water build up in my washer.

  2. 5 out of 5

    Fabulous! Love this product!

  3. 5 out of 5

    Hard Water - Big Help I bought a new washing machine and could no longer use my Calgon water softener since not OK for HE machines. Found Charlie’s Soap online and made orders for the liquid laundry soap and hard water booster. My clothes now come out not so stiff and the white stains I used to find on my dark clothes (from the hard water) are almost gone. Sometimes I see a little white on one piece of clothing but that’s much better than many pieces with large white stains.

  4. 5 out of 5

    Excellent I've been using this for years and I just love it. When I run out I definitely notice a difference in the clothes. Not nearly as soft as I want them. And it doesn't make me itch! Bonus!

  5. 5 out of 5

    Hard water treater I won't use anything else but Charlie's Soap for my laundry, and now I'm adding Charlie's Soap Booster, too. We have extremely hard water in our region and this product makes the laundry detergent work even better. Charlie's is as toxin-free as you can find, and it works wonderfully. Just say no to grocery store laundry products, especially dryer sheets, and the toxic perfumes they contain. Your machines will work better, longer, without getting gummed up by fabric softeners. The only difference you'll notice after you go without fabric softeners is your towels will be far more absorbent.

  6. 5 out of 5

    Booster This product is the one my washer needed: our water is extremely hard, and though I valued Charlie's products, something was needed to finalize the cleaning process. Thank you whoever came up with this. I highly recommend any product that Charlie's makes. They are effective besides being good for the environment..

  7. 5 out of 5

    New User I had purchased Charlie's Soap and then discovered that I needed the Booster also. My area does have hard water and I don't have a water softener. I like Charlie's Soap and now with the booster my clothes are softer. These products clean clothes and leave them fresh smelling and not just out of the washer. I used to use a free liquid detergent and my clothes always had an odd odor. No so with Charlie's Soap and Booster. Just fresh clean laundry. I have an HE Top Loader. Now I would replace it in a heartbeat with my old style washer if they still made them but I think we are stuck with HE machines. So if you have problems with your liquid soap leaving your clothing smelling like you never did laundry, give this product a try. I also have sensitive skin and have had NO reaction to Charlie's Soap and Booster. Thanks for making such a great product.

Only logged in customers who have purchased this product may write a review.