Is Bar Soap or Liquid Soap Better for Hand Washing?

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By Ozark River Manufacturing

July 29, 2025

When you’re stocking the sink with supplies, you’re faced with a choice: bar soap or liquid soap? You may have a personal preference, but is one more effective at removing bacteria than the other? Is liquid soap better for dry skin? Is using bar soap from a soap dish more likely to spread germs? What about the environmental impact? Is one more eco-friendly than the other?

What Is Soap?

The basic soap recipe has two parts: a weak fatty acid (like vegetable oil or animal fat) and a strong base, like lye. When these two parts are mixed and subjected to heat or cold, you get an alkali salt, or soap. To be clear, while lye itself is dangerous, it undergoes a chemical change during the soap-making process, which renders it safe.

Bar soap is the solid version of this concoction. Without getting too deep into the details, the mixture is strained or extruded until just the solids remain, then pushed into a mold and cut into soap bars. Standard liquid soap is also strained, but only until it’s a paste. Other liquids are added to this paste until it reaches the desired consistency.

What Isn’t Soap

What we think of as soap is called toilet soap, and it’s used for washing, bathing, and general house cleaning. But whether it’s bar soap, liquid hand soap, or even dishwashing soap, it probably isn’t toilet soap or even soap!

The FDA determines what is and isn’t soap, and according to them, “today there are very few true soaps on the market.” Technically, most of what we call “soap” is a “synthetic detergent product.” That’s because most “soaps” contain sodium lauryl sulfate, likely listed as SLS on the ingredient list. It’s a surfactant, which is a fancy way of saying “it helps get dirt out of things.” But because most soaps have SLS, the FDA says it’s not really soap, even if that’s what we call it.

Most manufacturers use SLS in their soaps for two reasons. First, it’s less expensive than traditional or true soap ingredients. Second, surfactants are sudsier, which makes bathtime more fun and means they don’t form soap scum that sticks around like “true” soap does, something most consumers appreciate.

Bar Soap vs. Liquid Soap for Handwashing?

So, that’s what soap is and isn’t, but is it better to use bar soap or liquid hand soap to wash your hands? Is one more effective at removing germs than the other? Is liquid soap more eco-friendly than bar soap?

How the Bar Soap vs. Liquid Soap Debate Started

In 1983, researchers wondered how sanitary bar soap is. In the name of science, they conducted a study that ultimately concluded bar soap could potentially spread germs. The key word is “potentially,” since the study also found that even though contamination was most likely to happen when bar soaps are used in a public setting, the risk was low. 

The study was cited as a reason not to use bar soap, despite the researchers pointing out that the study found a small risk of contamination, and only when bar soap is used in public settings. And though subsequent studies found there was little to no risk of cross-contamination from using bar soap, the concern persists to this day.

So, what does more recent research have to say on the subject?

Ultimately, bar soap and liquid hand soap are equally effective at removing germs. That said, there are some differences in environmental impact, performance, and shelf life. Here’s how the two soaps compare.

Bar SoapLiquid Hand Soap
Environmental impact of packagingGenerally packaged in cardboard, which is slightly better for the environment, but includes plastic wrapping, which has a bigger impactGenerally packaged in plastic bottles. Buying a large plastic bottle instead of multiple small ones mitigates the impact
Environmental impact of ingredientsMore likely to use animal-based products, but as a by-product, which lessens the environmental impact.More likely to use vegetable or palm oils, which have a stronger impact on the environment with regard to land use and carbon emissions.
Shelf lifeHas less liquid, which tends to increase shelf lifeHas more liquid, which can decrease shelf life, but is less drying on skin
Antibacterial properties of plain soapsEffective at killing germs but less so unless an antibacterial agent is addedEffective at killing germs, but more antibacterial, especially when it contains botanical oils

How Are Bar Soap and Liquid Soap Similar?

Interestingly, there are some areas where bar soap and liquid soap are no different.

While bar soap and liquid soap both have some negative impacts on the environment, ultimately, the biggest impact comes from how people use the soap. For example, letting the water run when you don’t need to, or using, believe it or not, water that’s too hot or cold.

Liquid soap is less effective in cold water, and while bar soap will work in cold water, someone who wants to wash their hands in hot water may let the water run and run and run to get it to warm up. Ultimately, studies have concluded that both kinds of soap work best in lukewarm water.

Finally, both bar soap and liquid soap create a rich lather, which indicates they both clean well and are equally likely to get your hands clean.

What Do Health Experts Think?

The Centers for Disease Control (CDC) and World Health Organization (WHO) agree that the type of soap you wash your hands in matters far less than your hand washing technique. Following proper hand washing guidelines is your best bet to ensure you get rid of germs on your hands.

That said, the CDC does say that in shared or public settings, liquid soap in a sealed container is better than a bar of soap for reducing any possibility of cross-contamination. The WHO doesn’t have as strong a recommendation, but states that bar soap needs to be well-drained and dry to prevent microbes from remaining on the soap and around the soap dish.

Your Hand Washing Technique Matters Most

Ultimately, it doesn’t matter if you use a bar of soap or liquid soap to wash your hands. Following the hand washing steps and using lukewarm water has the biggest impact on germs, bacteria, and other microbes — not to mention, dirt!

However, in a public setting, bar soap may be impractical. You need a place to put the soap dish and a way to ensure the bar of soap and dish don’t fall into the sink or on the ground. What’s more, there’s the possibility that bar soap increases cross-contamination, making liquid soap the more practical option.

Fortunately, many of Ozark River Manufacturing’s portable sinks include an integrated, easy-to-fill, liquid soap dispenser, ensuring people can wash their hands in soap and running water. Our portable sinks allow you to have a sink without plumbing and are perfect for a wide variety of industries, including:

Contact us today to learn more about our portable sink solutions or browse our full line-up of portable sinks.

Sources:

The Environmental Impacts of Bar Soap Production: Uncovering Sustainability Risks with LCA Analysis

Comprehensive evaluation of physico-chemical, antioxidant, and antimicrobial properties in commercial soaps: A study on bar soaps and liquid hand wash – ScienceDirect

A LCA case study of hand washing with liquid and bar soap

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Ozark River Manufacturing designs and delivers top-quality, NSF-certified portable sinks. Since 2006, our inventive and bold team has ensured health compliance with quick-connect tanks and instant hot water. With over 55 models, we provide solutions for every need, backed by exceptional customer support and timely delivery. Healthy people matter, and we make a positive impact every day.

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