Charlie's Soap Laundry Booster & Hard Water Treatment Powder comes in a 2.64 lb (1.2 kg) bag with a purple and white leaf-patterned design, highlighting stain removal, whitening, and powerful laundry boosting benefits. Back of a purple Charlie's Soap Laundry Booster & Hard Water Treatment Powder bag featuring a white floral design, instructions, usage directions, warnings, barcodes, logos, and QR code in black and white text. A bag of Charlie's Soap Laundry Booster & Hard Water Treatment Powder sits on a windowsill beside a white bowl filled with light blue laundry, as sunlight brightens the clean, minimal setting. Text on a green background about 3,000 banned ingredients and a higher standard for home products.
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Charlie's Soap Laundry Booster & Hard Water Treatment Powder comes in a 2.64 lb (1.2 kg) bag with a purple and white leaf-patterned design, highlighting stain removal, whitening, and powerful laundry boosting benefits.

Charlie's Soap Laundry Booster & Hard Water Treatment Powder

2.64 lbs

Why we love it

  • Free from 3,000+ banned ingredients and meets our EU-informed standards.
  • Helps laundry detergents work more effectively by managing mineral-heavy hard water during the wash.
  • Reduces mineral buildup on fabrics to help clothes and linens feel softer over time.
  • Compatible with all washing machines and effective in both hot and cold water cycles.
Scent: Fragrance Free
Purchase options

Laundry Booster & Hard Water Treatment Powder $27.99

Free carbon neutral shipping on orders $29+. Arrives in 3–5 days. Free, easy 30-day returns.

Charlie’s Soap Laundry Booster & Hard Water Treatment is designed to help laundry detergents work more effectively in hard water conditions, where minerals like calcium and magnesium can interfere with cleaning results.

Hard water minerals can cling to fabrics during washing, leaving clothes looking dull, feeling stiff, and harder to rinse clean. Over time, those same minerals can also build up inside washing machines, making detergents less effective. This booster is formulated to address those conditions during the wash cycle, allowing detergents to perform the way they’re intended to.

What it does in the wash:
When added to the wash, the booster helps manage mineral-heavy water so detergent can interact more freely with fabrics. This allows dirt, oils, and everyday buildup to release more easily and rinse away more thoroughly during the rinse cycle.

What to expect over time:
Because mineral buildup doesn’t disappear overnight, it may take a few wash cycles to notice the full effect. With continued use, fabrics can wash cleaner and feel softer as old mineral residue is reduced and detergent performance becomes more consistent from load to load.

Where it fits best:

  • Homes with hard or mineral-heavy water
  • Laundry that feels stiff or looks dull after washing
  • Towels, linens, and everyday clothing
  • Use alongside liquid or powder detergent


Using a concentrated booster:
The booster is concentrated, so small amounts are used per load. Measuring as directed helps it dissolve properly and integrate into the wash cycle. It works in both hot and cold water and is compatible with standard and high-efficiency washing machines.

Part of a simple system:
Used alongside Charlie’s Soap Laundry Liquid or Laundry Powder, the booster helps create more consistent cleaning results without relying on fabric softeners or added laundry products.

Potassium Diphosphate

Use one half tablespoon per regular load Use one tablespoon for hard water or heavily soiled loads Add directly to washing machine drum Use with powder or liquid laundry detergent Wash using hot or cold water Suitable for standard and high efficiency machines

Grove Values

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3,000+ BANNED INGREDIENTS

Cleaners that care for your home like you do.

Every cleaning product is screened against strict ingredient and material standards to help you clean more safely and sustainably.

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Nothing harsh, no compromises

No ammonia, chlorine bleach, phthalates, or formaldehyde donors

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Cruelty free

Every cleaning brand we offer is committed to cruelty-free practices

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Less waste, less plastic

Refillable formats and plastic-free tools that help limit microplastic exposure

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Go Beyond Plastic™ and microplastics.

Plastic products break down into microplastics that can affect human health.

Grove Co. is on a mission to reduce plastic in home essentials — for both people and for the planet.

Learn more on the Home Planet blog