The Difference Between Dish Soap, Dishwasher Detergent, and Laundry Detergent (and Why it Matters)

The Difference Between Dish Soap, Dishwasher Detergent, and Laundry Detergent (and Why it Matters)
Photo: DUO Studio, Shutterstock

Recently, I wrote about some of the lesser-known cleaning applications of dishwasher tablets around the house. In the comments, someone asked, “What’s the difference between dissolving the pods in warm water and using that to clean instead of…you know, soapy water?”

It’s a valid question. What is the difference between standard-issue dish soap that you use to hand-wash plates and the liquid or powder that goes in the detergent compartment of your dishwasher? And is any of it interchangeable with laundry detergent? (Quick answer: No. Read on to find out why.)

How dish soap and detergents are the same

Essentially all detergents are designed to break up oils so they can be washed away — and they do contain similarities. Across the board, all three typically contain surfactants to reduce surface tension, allowing water to spread out and wet the entire surface you’re trying to clean; enzymes to break down food, stains, and dirt; builders to keep hard water minerals at bay; colours and fragrances to give the product its distinctive look and smell; and preservatives to enhance their shelf life. (Additionally, solvents keep liquid soaps from separating and some dish soaps and detergents contain antibacterial and disinfecting ingredients.)

How liquid dish soap and dishwasher detergent are different

But there are key differences in the ingredients of dish soap, dishwasher detergent, and laundry liquid that make each one best suited for its particular environment. According to the University of Wisconsin-Madison, “The main differences are in the pH, presence or absence of bleach, and the types of surfactants — long molecules that are water-loving at one end and oil-loving at the other.”

Where dishwasher detergents are designed to dissolve food and oil with blasts of high pH and chlorine bleach, liquid dish soap contains no bleach and milder surfactants, so as not to irritate our hands. Dishwasher detergent, according to Bob Vila, is also formulated to clean without the thick, foamy suds of liquid dish soap, instead relying on enzymes to break down food protein chains and starches into small enough parts they can be washed away.

Dish soap contains “mildness additives,” such as oils and moisturizing agents since it’s designed to come in regular contact with human skin. Also, as the name soap would suggest, it’s formulated to use thick, bubbly suds to dissolve food and oils (rather than enzymes).

To recap: Dishwasher detergent contains bleach and enzymes not found in dish soap — which is sudsier and milder for our hands. Don’t put liquid dishwashing soap in your dishwasher. (Unless you’re trying to recreate the “Jack versus the appliances” scene from Mr. Mum.)

What about laundry detergent?

Laundry products occupy a middle ground between the general mildness of dish soap and the bleach-based ardor of dishwasher detergent. According to HomeSteady, laundry liquids “include builders which enhance the cleaning efficiency of the surfactant by inactivating water hardness minerals; polymers (also known as antiredeposition agents) which help capture and hold soils and dyes, sending them down the drain to avoid re-depositing on washed fabrics; oxygen bleach which maintains colour and whiteness; softeners which reduce fabric friction or static electricity; and corrosion inhibitors which protect the parts of washing machines from corrosion.”

Translation: While laundry detergent is better at removing stains from clothes, it’s more harmful to your skin than hand-washing dish soap (but less harmful than dishwasher detergent, the harshest of them all).

Are any of them interchangeable?

What if you run out of laundry detergent — can you use dish soap in your washing machine? According to SFGate, while dish soap and laundry detergent are similar, they’re formulated with different additives. “Dish soap typically contains additives that are designed to keep your hands soft while you wash dishes, while laundry detergent contains softeners to keep clothing wrinkle- and static-free.”

Dish soap also creates a lot more suds. If you need to use dish soap in an emergency when the laundry simply must be done, use only one to three teaspoons. And make sure it’s bleach and fragrance free — unless you want to smell like a freshly washed plate.

Don’t ever put dishwasher detergent in your washing machine — and if you do want to put its grime-busting properties to good use in other areas of your home, protect your hands with rubber gloves.

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