Hot potting is the practice of soaking in natural hot springs or geothermal pools. It ranges from a relaxing dip in a lukewarm mineral spring to a genuinely dangerous plunge into superheated water that can cause fatal burns in seconds. The term is most commonly associated with geothermal areas like Yellowstone National Park, where the line between a pleasant soak and a life-threatening situation can be just a few feet apart.
How Hot Springs Form
Hot springs occur where groundwater comes into contact with geologically heated rock beneath the earth’s surface. The water rises through cracks and fissures, picking up dissolved minerals along the way, and emerges at temperatures well above the surrounding air. A body of water qualifies as a hot spring at 122°F (50°C), but many geothermal features run far hotter than that, sometimes exceeding the boiling point. In places like Yellowstone, some pools sit at temperatures above 200°F.
The appeal is obvious. Warm mineral water in a natural setting feels luxurious, and many cultures have bathed in hot springs for centuries. But naturally occurring pools don’t come with thermostats or warning labels, and their temperatures can shift without notice due to underground changes in geothermal activity.
Why Hot Potting Is Dangerous
The most immediate risk is thermal burns. At 140°F (60°C), it takes roughly 3 seconds of skin contact to produce a serious burn. Many geothermal pools far exceed that threshold, and the water often looks deceptively calm. Unlike a pot on a stove, there’s no steam or bubbling to signal danger at every temperature. People have stepped into pools expecting a warm soak and instead suffered burns covering large portions of their body.
Since 1872, at least 22 people have died from scalding in Yellowstone’s thermal features, with hundreds more injured. That death toll is more than double the number of fatalities from bear and bison encounters combined, according to the U.S. Geological Survey. The first recorded hot spring death in the park was in 1890, and the most recent was in July 2022. Some of these deaths involved people who left designated boardwalks and broke through thin ground crusts into boiling water beneath. In at least one case, a victim’s body dissolved entirely in the acidic, superheated pool before it could be recovered.
Infection Risks in Warm Water
Heat isn’t the only hazard. Warm freshwater is a natural habitat for dangerous microorganisms that don’t survive in cooler or chlorinated water.
The most alarming is a single-celled organism called Naegleria fowleri, sometimes called the “brain-eating amoeba.” It thrives in warm freshwater environments including hot springs, lakes, and rivers. If contaminated water is forced up the nose, the organism can travel to the brain and cause primary amebic meningoencephalitis (PAM), a brain infection that destroys tissue rapidly. PAM is nearly always fatal; survival is extremely rare. The infection cannot spread from drinking the water or from person to person. It specifically requires water entering the nasal passages, which is why diving, jumping, or dunking your head in warm freshwater carries the highest risk.
Beyond amoebas, recreational hot springs harbor a range of opportunistic bacteria. Research sampling 29 hot springs found that species of Acinetobacter and Pseudomonas dominated the microbial communities in pools used for recreation. Many of these bacteria showed resistance to multiple antibiotics. For people with weakened immune systems, open wounds, or chronic illnesses, exposure to these organisms carries a meaningful infection risk that healthy bathers might never notice.
Where Hot Potting Happens
Hot potting is practiced wherever accessible geothermal features exist. Iceland, New Zealand, Japan, and the western United States are all popular destinations. In some locations, hot potting is legal and even encouraged at developed sites with monitored temperatures and basic safety infrastructure. In others, it’s explicitly banned.
Yellowstone National Park prohibits entering any thermal feature. The park’s hydrothermal areas are unpredictable, and the ground surrounding many pools is a thin crust over boiling water. Other locations, like certain hot springs in Idaho, Colorado, or Oregon, allow soaking in natural pools where water temperatures have been measured and are known to be safe. The distinction matters enormously. A developed hot spring with a posted temperature of 104°F is a fundamentally different experience from an unmarked geothermal pool in the backcountry.
How to Reduce Risk
If you’re planning to soak in a natural hot spring, a few precautions make a significant difference. First, only use springs with known, posted temperatures or where other bathers can confirm conditions. Water temperature can vary dramatically within the same pool, especially where a hot source mixes with a cold stream. Test the water gradually before getting in, and avoid any pool where you can’t comfortably hold your hand submerged for several seconds.
Keep your head above water. This single habit dramatically reduces the risk of Naegleria fowleri infection by preventing water from entering your nose. Nose clips offer additional protection if you plan to submerge. Avoid swallowing the water, and stay out entirely if you have open cuts, recent surgical wounds, or a compromised immune system.
Respect closures and barriers at geothermal parks. The boardwalks and fences at places like Yellowstone aren’t suggestions. The ground near thermal features can look solid while being only inches thick over scalding water or mud. Staying on marked paths is the single most effective way to avoid the kind of accidents that have killed visitors for over a century.