Sharing our Science-based Formulation Expertise with You

Winning the Hard Water Battle: Optimizing Detergent Performance in the Face of Water Hardness

In this article, you will read:


Hard water causes a number of undesirable consequences for homeowners, particularly when it comes to laundry. The presence of calcium and magnesium ions in hard water negatively affects detergent performance, leading to inefficient cleaning and potential damage to clothing and textiles. In this article, we will explore the nature of water hardness, its impact on detergents, and strategies to optimize detergent formulas to deliver excellent cleaning results even in the presence of hard water.

Understanding Water Hardness

A. Definition of water hardness

Water hardness is primarily defined by the concentration of calcium and magnesium ions present in the water. The hard water minerals interact with various chemicals in the detergents, adversely affecting their cleaning performance.

B. Common causes and sources of hard water

Hard water minerals usually come from groundwater sources, such as wells or aquifers, where water passes through rocks rich in calcium and magnesium. The level of water hardness can vary depending on the geological makeup of the region and the source of the water supply.

C. Measuring water hardness levels

Water hardness is generally measured in grains per gallon (gpg) or parts per million (ppm) of calcium carbonate (CaCO3) equivalent. Water with a hardness level of more than 17.1 ppm is considered hard, while anything above 180 ppm is classified as very hard water.

Tap limescale caused by hard water

How Water Hardness Affects Detergent Performance

A. Interaction between hard water ions and detergents

Hard water minerals form insoluble compounds with soap, reducing the efficacy of cleaning agents. Additionally, they can interact with surfactants in synthetic detergents and decrease their ability to form micelles, which are crucial for trapping dirt and grease.

B. Impact on cleaning properties

The presence of hard water minerals can reduce the overall cleaning performance of detergents. Clothes washed in hard water may not come out as clean as they should, and the buildup of minerals on fabrics can leave them feeling stiff and rough.

C. Influence on foamability and foam stability

Hard water can affect the formation and persistence of foam in detergents. As a key property for effective cleaning, foam aids in the suspension of dirt particles and their subsequent removal. Hard water interferes with foam by reducing foamability and stability, leading to diminished cleaning action.

Common Hard Water Problems in Laundry

A. Minerals buildup and fabric stains

Hard water can cause the buildup of mineral deposits on clothing and fabrics, leading to discoloration and stiffness. This buildup can also leave distinguishable chalky white or gray stains on clothing, especially on dark-colored fabrics.

B. Damage to clothing and textiles

Continual exposure to hard water during the laundering process can cause fibers in fabrics to weaken and break, leading to a shorter lifespan for clothing and textiles.

C. Skin irritation and sensitivities

The residual minerals left on fabric by hard water can cause skin irritation and exacerbate existing skin sensitivities, such as eczema or psoriasis.

Washing clothes in washing machine tub

Detergent Formulation: Key Components and Surfactants

A. Nonionic surfactants

Nonionic surfactants are a common ingredient in detergent formulations. They are less affected by the presence of multivalent ions (hard water) than other types of surfactants and are generally milder on skin, dyes, and fabrics. Cocamide DEA, Fatty Alcohol Polyoxyethylene Ether(AEO-7/ AEO-9), and Alkyl Polyglycoside are the common nonionic surfactants widely used in detergent formulas, for their excellent hard-water resistance and other properties.

B. Anionic surfactants

Anionic surfactants are widely used in detergents due to their good cleaning performance and high levels of foam generation. However, they can be more susceptible to the negative effects of hard water minerals. It’s worth noting that different anionic surfactants have varying levels of hard water sensitivity, which can influence their effectiveness in hard water conditions.

Linear Alkyl Benzene Sulphonic Acid (LABSA), Sodium Lauryl Ether Sulfate (SLES), Sodium Lauryl Sulfate (SLS), and Alpha Olefin Sulphonate (AOS) are the four most commonly used anionic surfactants in detergents. In terms of their sensitivity to hard water, LABSA has the highest sensitivity, followed by SLES and SLS, which have similar sensitivity levels. AOS has the lowest sensitivity among these four surfactants. This ranking of hard water sensitivity can be represented as: LABSA > SLES ≈ SLS > AOS.

C. Key role of builders in aiding the cleaning process

Builders are components in detergents that help to enhance the overall cleaning performance. They act in various ways, such as softening the water by binding to hard water ions and maintaining the appropriate pH levels for effective cleaning.

Optimizing Detergent Formulas for Hard Water

A. Using surfactants with low sensitivity to calcium and magnesium ions

Selecting surfactants that are less affected by hard water minerals can improve cleaning efficiency. To achieve the best cleaning performance in different conditions, including hard water, it is recommended to formulate with a primary surfactant (usually an anionic surfactant, LABSA for powder detergents, and SLES for liquid surfactants) and combine it with one, two, or even three secondary surfactants to achieve a synergistic effect. Some of the common effective surfactant combinations in detergents include:

Type of DetergentSurfactant CombinationApplication
Powder DetergentsLABSA + AOSHigh-foaming hand washing
LABSA + SLSHigh-foaming hand washing
LABSA + AEO-9Low-foaming machine washing
Liquid DetergentsLABSA + SLES + CDEAHigh-foaming hand washing
LABSA + SLES + CAPBHigh-foaming hand washing
SLES + CDEAHigh-foaming hand washing
SLES + CAPBHigh-foaming hand washing
SLES + AEO-9Low-foaming machine washing
Surfactant Combinations for Optimal Detergent Performance in Hard Water Conditions

By incorporating these surfactant combinations, detergents can be tailored to suit different application requirements, such as high-foaming hand washing or low-foaming machine washing, while also ensuring efficient and effective performance in hard water conditions.

B. Incorporating chelating agents and water softening agents

Chelating agents, such as ethylenediaminetetraacetic acid (EDTA), are usually added to liquid detergents to sequester hard water ions and prevent them from interfering with the cleaning action. By binding to the calcium and magnesium ions, chelating agents effectively neutralize the effects of hard water.

However, in powder detergents and soaps, Sodium tripolyphosphate (STPP) or 4A zeolite is commonly added as a water softener. The addition ratio is often not small, commonly ranging from 5% to 15%. This is because, in powder detergents, LABSA is often the primary surfactant, and in bar soaps, soap (such as sodium stearate, sodium palmitate, or sodium oleate) is the primary surfactant. Both LABSA and soap are highly sensitive to hard water, so a significant amount of water softener is necessary to guarantee effective cleaning performance.

The use of chelating agents and water softening agents in detergents helps to mitigate the negative effects of hard water on the cleaning process, ensuring that the surfactants can work effectively and provide satisfactory results.

C. Adding suspension agents to prevent re-depositing on fabrics

Incorporating suspension agents in detergent formulations can help keep soil particles and mineral deposits suspended in the water, preventing their reattachment to fabrics and ensuring a cleaner wash.

For powder detergents, carboxymethyl cellulose (CMC) is commonly used as a suspension agent. CMC is a water-soluble polymer derived from cellulose, exhibiting excellent suspension and stabilization properties. It effectively prevents soil particles and minerals from settling back onto fabrics during the washing process and contributes to a cleaner and brighter appearance of the washed items.

In the case of liquid detergents, sodium polyacrylate is typically employed as a suspension agent. Sodium polyacrylate is a super-absorbent polymer that can absorb and retain large amounts of water, forming a gel-like substance. This property makes it particularly effective in creating a stable suspension of soil particles and mineral deposits in the wash water, preventing them from settling back onto the fabrics and maintaining the overall cleaning performance of the detergent.

In addition to CMC and sodium polyacrylate, other suspension agents like xanthan gum, guar gum, and hydroxyethyl cellulose (HEC) can also be used in detergent formulations for similar purposes. By incorporating effective suspension agents in detergents, manufacturers can create products that deliver enhanced cleaning results, even in challenging hard water conditions.

D. Implement Enzyme-Enhanced Formulations

Enzymes are biological catalysts that can enhance cleaning efficiency, particularly in cold and hard water conditions, by targeting specific stain components that might be harder to remove due to the presence of minerals. Some commonly used enzymes in detergent formulations include proteases, lipases, and amylases, each targeting different types of stains. The use of enzyme-based detergents in hard water can improve overall cleaning performance, as the enzymes work synergistically with surfactants to break down and remove challenging stains that can be more stubborn when minerals are present in the wash water.

Washing clothes in a basin

Comparative Performance of Powder and Liquid Detergents in Hard Water

A. Pros and Cons of Powder Detergents


  1. Powder detergents tend to offer more potent cleaning power and are often more cost-effective than liquid detergents.
  2. They are particularly efficient in removing dirt and grime from fabrics.


  1. The primary surfactant in powder detergents, LABSA, can be negatively affected by calcium and magnesium ions in hard water.
  2. To maintain effective cleaning in hard water conditions, powder detergents may require an increased dose (10-15% to >30%) than what is typically recommended.

B. Pros and Cons of Liquid Detergents


  1. Liquid detergents are often considered more convenient and easier to use than powder alternatives.
  2. They dissolve well in water and can be more effective at removing oil and grease stains.


  1. The efficacy of liquid detergents in hard water conditions may be somewhat reduced in comparison to soft water conditions.
  2. To achieve better cleaning results in hard water, the use of additives or treatment systems may be necessary.

Tips for Washing Clothes in Hard Water

A. Choosing the right detergent for hard water

Selecting a detergent designed specifically for hard water conditions can help improve cleaning performance. Look for products that contain water softeners or chelating agents to minimize the impact of hard water minerals.

B. Adding water softeners and appropriate dosages

Water softeners can be added to the wash cycle to help combat the negative effects of hard water. Follow the manufacturer’s instructions to determine the appropriate dosage for your water hardness level.

C. Proper water temperature and load size for optimal cleaning performance

Using the proper water temperature and adhering to recommended load sizes can improve the cleaning efficiency of detergents in hard water conditions. Hot water is generally more effective at dissolving hard water minerals, but take care to ensure you are using the recommended temperature settings for the specific fabrics being laundered.

Liquid detergent label with water softener

DIY Solutions: Utilizing Vinegar in Hard Water Laundry

A. Benefits of using vinegar in the wash cycle

White vinegar is a natural and cost-effective solution for combating hard water in laundry. It can help to dissolve mineral deposits, soften fabrics, and even neutralize any lingering odors.

B. Detailed instructions for incorporating vinegar into laundry routines

Add approximately half a cup (120 ml) of white vinegar to the washing machine during the rinse cycle. It is important to note that vinegar should not be mixed directly with bleach or detergents containing bleach, as this can create harmful fumes.

C. Potential limitations and drawbacks

While vinegar is a practical DIY solution for hard water laundry issues, it may not be as effective as specially formulated detergents or water softening systems. It may also not be suitable for fabrics that are sensitive to high-acid solutions.


In conclusion, water hardness presents substantial obstacles to detergent performance, resulting in less effective or even harmful laundry outcomes. As industry insiders, understanding the intricacies of hard water, its impact on detergents, and approaches for optimizing detergent formulas can enable us to develop innovative solutions for tackling hard water challenges. By creating and promoting the appropriate products and best practices that address hard water issues, we can provide value to consumers, enhance their laundry experience, and secure a competitive edge in the market, ultimately resulting in long-term benefits for our business, as well as for clothing, textiles, and appliances.

Frequently Asked Questions

1. What is the ideal detergent for hard water?

An ideal detergent for hard water should contain water softeners and chelating agents to minimize the impact of hard water minerals. Opting for enzyme-based or low-pH formulas may also help in tackling hard water challenges.

2. Can ion-exchange water softeners improve detergent performance in hard water?

Yes, ion-exchange water softeners can improve detergent performance by exchanging calcium and magnesium ions for sodium ions, thereby softening the water and allowing detergents to work more effectively.

3. How can I maintain the efficiency of my washing machine in hard water conditions?

Proper maintenance, including regular cleaning, inspection of hoses and connections, and using the appropriate detergent formulas designed for hard water, can help maintain the efficiency of your washing machine in hard water conditions.

4. How can I determine the hardness of my water at home?

There are various methods to measure water hardness at home, including test strips, water hardness testing kits, or consulting your local water provider. Understanding the hardness level of your water can help you make informed decisions about the type and dosage of detergents to use for optimal cleaning performance.

5. Can I use softening agents in combination with enzymes for improved cleaning in hard water conditions?

Yes, combining softening agents with enzyme-based detergents can provide a synergistic effect, improving overall cleaning efficiency in hard water. The softening agents help reduce the negative impact of mineral ions, allowing the enzymes to work effectively to break up and remove stubborn stains. Always follow the manufacturer’s recommendations regarding the use and dosage of detergent additives.

Written by:
Jun Xie
Jun Xie
Jun is the head of R&D at Yeser Chemicals. He holds a master's degree in Chemical Engineering and Technology. After joining Yeser Chemicals in 2013, he has been dedicated to researching and developing new coconut-based green surfactants and their safe uses in Home & Personal care products. In addition to serving as the Head of R&D at Yeser Chemicals, Jun is the director of the Guangdong Green Surfactant Engineering Technology Research Center and a member of the Standard Committee of Guangdong Daily Chemical Chamber of Commerce.

Yeser Chemicals is a leading producer of CAPB, CDEA, CMEA, EGDS, and other various Coconut-derived surfactants.

By self-manufacturing and 3rd-party toll-manufacturing, we provide a long list of safe ingredients, including surfactants, conditioners, thickeners, etc.,  used in Home & Fabric Care, Personal Care, and Cosmetics.

Have A Demand? Or A Question?

Share this post with people

You may also enjoy

Get In Touch

And find out how we can bring your business to the next level.

No.8, Petrochemical No.3 Road, Shatian Town, Dongguan city,  China

Room 1005, No. 408, Guangyun Road, Jiahe Street, Baiyun District, Guangzhou City, China

A Dedicated Supporting Team Standing By