What is Thick Water?

Thick water is water mixed with a food-grade thickening agent to make it safe and easier to swallow. It is used by people with dysphagia — difficulty swallowing — who cannot safely drink regular thin liquids. Thickening slows the flow of the liquid, giving the person more control and reducing the risk of liquid entering the airway.

When I started SimplyThick back in 2001, it was hard to imagine that someday our work to make water thick would become a brief viral challenge. In 2021, of course, there was a TikTok thickened water challenge. It was a weird way for some acquaintances to figure out what we do at SimplyThick. And since 2021, the trend seems to comes and go with some regularity.

Of course, the problem with the TikTok challenge is that the "best" videos showcase the strongest negative reactions to a product that makes someone's life better every day.

To understand why thick water exists, you need to know what dysphagia is. Then, I will explain thick water and how it helps.

What is dysphagia?

Dysphagia is the medical term for difficulty swallowing or swallowing problems. For people with dysphagia, this is not a once-in-awhile issue. Problems occur with most or all of their swallows every single day. Dysphagia can happen at any age and for many reasons. Almost half of all swallowing problems stem from neurologic conditions like Parkinson's Disease, strokes, ALS (Lou Gehrig's disease), brain tumors, head and neck cancers, or recent intubation of the trachea.

People with dysphagia experience problems when they swallow food or drink and often experience a choking sensation. Eating and drinking become a chore. People with dysphagia need to make sure they eat and drink enough to avoid dehydration and malnutrition. Some people with dysphagia have difficulties eating enough food to maintain weight and energy. Or they may have trouble drinking enough water or other fluids to stay hydrated.

Dysphagia is a serious medical condition with a variety of causes and treatments. Do not self-diagnose or self-treat. If you think you or a loved one has dysphagia, seek medical attention.

What is thick water, and how does it help?

Thick water is simply plain, ordinary water that is thickened to allow a person with dysphagia to swallow the water safely and properly. It is a simple way for some people with dysphagia to handle their liquids. Thickening helps by slowing the liquid in their mouth. They can better control the drink. They can swallow it without trouble.

The reason we prefer to thicken water and other liquids is that the alternatives to thickened beverages may be less desirable — feeding tubes, for example. With thick water (and any other liquids), the person is still eating and drinking with their mouth. Generally, the least invasive option — thick water — is preferred to the alternatives.

How thick is thick water?

Thick water comes in 5 thickness levels, according to the International Dysphagia Diet Standardisation Initiative (IDDSI). Each level represents a specific amount of thickness. A speech-language pathologist or physician will prescribe the level that is right for the individual.

• Level 0 — Thin Liquids: These are normal, everyday liquids like water, coffee, tea and soda.

• Level 1 — Slightly Thick: Just a little thicker than water. Flows easily from a cup, similar to a light syrup.

• Level 2 — Mildly Thick: Flows off a spoon more slowly than water. Can be sipped from a cup with a little more effort than a thin liquid.

• Level 3 — Moderately Thick: Pours slowly and dollops off a spoon. Still drinkable from a cup but requires effort. Often compared to honey.

• Level 4 — Extremely Thick: Cannot be poured from a cup. More likely to be eaten with a spoon than sipped — similar to a yogurt consistency.

IDDSI has a few simple, easy tests that ensure the thick water is precisely the thickness that works best for the specific person. Another benefit is that the IDDSI tests are accomplished relatively quickly and inexpensively at home. Watch how simple it is to conduct the IDDSI flow test designed to measure the thickness of the water.

For facility staff and healthcare professionals: IDDSI is now the recognized standard of care in the U.S., with enforcement beginning in California in January 2026. Learn what the regulatory landscape looks like and what your facility needs to know.

Would you choose thick water for a loved one?

Thick water serves a crucial role in the lives of people with dysphagia. Swallowing problems can make drinking water difficult — even dangerous. In many cases, thick water makes it possible to continue drinking and staying hydrated without more invasive interventions.

If you are a caregiver or healthcare professional looking to go deeper on this topic, my YouTube channel covers the IDDSI flow test, how to thicken liquids correctly, and much more. If you are just getting started with IDDSI, IDDSI.org has free training resources and testing materials available to anyone.