Beginner's Complete Guide to
Thermal Mineral Waters

You've seen the steam rising from a pool surrounded by mountains. You've watched the viral TikToks of people soaking in turquoise mineral water with snow-covered peaks in the background. And now you're wondering: what exactly is a hot spring, why do people treat it like a religious experience, and how do you actually do it right?

This is the guide we wish we'd had. Whether you're planning your first visit to a hot spring resort or want to hike into a remote primitive pool in the backcountry, this complete beginner's guide to thermal mineral waters covers everything — the geology, the chemistry, the health science, the etiquette, and the ritual.

What Is Thermal Mineral Water?

Thermal mineral water is groundwater that has been heated by geothermal energy — the natural heat of the earth's interior — and has absorbed dissolved minerals as it moves through underground rock formations. By definition, water qualifies as "thermal" when it emerges from the ground at a temperature warmer than the mean annual air temperature of the surrounding region. In practice, most hot springs you'll visit range from a pleasant 98°F to a scalding 140°F or higher at the source.

What makes thermal water fundamentally different from a heated swimming pool or even a conventional hot tub is its mineral composition. As water percolates downward through rock — sometimes miles underground — it dissolves minerals from the surrounding geology: sulfur, magnesium, calcium, sodium, silica, lithium, bicarbonate, and dozens of trace elements. The exact mineral profile of any given spring is a direct fingerprint of the geology it passed through. This is why the water at Pagosa Springs in Colorado feels different from the water at Ojo Caliente in New Mexico, which feels different from the springs at Chena in Alaska.

Thermal vs. Hot Springs vs. Geothermal — What's the Difference?

These terms are often used interchangeably, but they have distinct meanings worth understanding:

• Hot spring — the general term for any naturally occurring spring where the water temperature is significantly warmer than ambient. The most common term in the U.S.
• Thermal spring — technically any spring warmer than mean air temperature; often used in European spa culture to describe medically-oriented mineral water facilities.
• Geothermal spring — emphasizes the volcanic or tectonic heat source; common in scientific and geological contexts.
• Mineral spring — emphasizes the dissolved mineral content rather than temperature; can include cold carbonated springs like Saratoga in New York.
• Hydrothermal vent — an extreme version found on the ocean floor; not relevant for soaking but the same geological process.

For the purposes of this guide — and for Geothermal Lifestyle as a whole — we use thermal mineral water to describe the full experience: water that is both geothermally heated and naturally mineral-rich. This is the water worth traveling for.

How Geothermal Water Works

Understanding where hot spring water comes from makes the experience considerably more meaningful. You're not soaking in a heated pool — you're soaking in water that fell as rain or snow thousands of years ago, sank deep into the earth, and made a long slow journey through volcanic geology before rising to meet you.

The Hydrological Journey

Here's how the water you're soaking in was made:

The Key Minerals &
What They Do

The specific mineral composition of any hot spring is what defines its character — both in terms of how it feels on your skin and what it may do for your body. Here are the primary minerals you'll encounter in American thermal springs and the roles they play:

Mineral	Common Sources	What It Does	Found In
Magnesium	Dolomite limestone	Muscle relaxation, nervous system regulation, sleep improvement, anti-inflammatory. Absorbs transdermally — soaking replenishes magnesium deficiency common in modern populations.	Durango, CO · Pagosa, CO · Most Colorado springs
Sulfur / Sulfate	Volcanic deposits, evaporite rock	Skin health and detoxification. Sulfate stimulates bile production and supports liver function. The distinctive "rotten egg" smell indicates hydrogen sulfide — a sign of truly geothermal water.	Most Western U.S. volcanic springs
Calcium	Limestone, chalk formations	Bone density support, cardiovascular regulation, skin barrier function. Forms the travertine formations common around many springs.	Travertine Hot Springs, CA · Arkansas springs
Sodium Bicarbonate	Carbonate rock	Softens skin dramatically. Alkaline water feels silky and leaves skin remarkably smooth. Ojo Caliente's soda spring is a classic example.	Ojo Caliente, NM · Saratoga, NY
Lithium	Granite pegmatite	Mood stabilization. Trace lithium in drinking water is associated with lower rates of depression in population studies. Present in many Colorado and Nevada springs.	Colorado · Nevada · Idaho
Silica	Volcanic / rhyolitic rock	Skin elasticity and wound healing. Silica-rich water leaves skin feeling extraordinarily smooth. Particularly high in volcanic spring regions.	Oregon · Wyoming · New Mexico
Iron	Ferrous rock deposits	Historically used for anemia treatment. Creates the characteristic orange-red staining around iron springs. Ojo Caliente maintains a dedicated iron spring.	Ojo Caliente, NM · Some Arkansas springs

Does the Smell Mean the Water Is Better?

One of the most common beginner questions: why do some hot springs smell like sulfur, and does that mean they're more therapeutic? The sulfur smell comes from hydrogen sulfide gas — a byproduct of sulfate reduction by bacteria in the spring system. Its presence does indicate a deeply geothermal, unprocessed water source. Whether the spring smells or not depends on the specific geology, not necessarily the mineral concentration overall. Some of the most mineral-rich springs in Colorado (like Ouray) are completely odorless. Don't use the smell as your sole quality indicator.

Health Benefits of
Mineral Soaking

The therapeutic use of mineral-rich thermal water — known as balneotherapy or hydrotherapy — has been practiced for thousands of years across every culture that had access to geothermal springs. Roman legions soaked in mineral baths for recovery. Japanese onsen culture has elevated the practice to a spiritual art form. European spa towns like Baden-Baden built entire economies around their springs. The modern American wellness movement is rediscovering what every ancient culture already knew.

Here's what the research and centuries of practice actually support:

Transdermal Mineral Absorption

The skin is not an impermeable barrier. Research in dermatology has confirmed that certain minerals — particularly magnesium sulfate — are absorbed through the skin during extended bathing. This is especially significant because an estimated 50–80% of Americans are magnesium deficient, and oral magnesium supplements have poor bioavailability. Soaking in magnesium-rich mineral water may be one of the most effective ways to replenish this critical mineral.

Nervous System Regulation

Immersion in thermal water at 100–104°F triggers a parasympathetic nervous system response — essentially shifting your body from "fight or flight" to "rest and digest." Heart rate decreases, blood pressure drops, cortisol levels fall. The combination of heat, buoyancy, hydrostatic pressure, and mineral absorption produces a state of deep physiological relaxation that is difficult to achieve through other means.

Musculoskeletal Recovery

Warm mineral water increases circulation, reduces muscle tension, and the buoyancy of immersion reduces gravitational load on joints. Multiple studies on balneotherapy have shown measurable improvements in pain and function for conditions including arthritis, fibromyalgia, lower back pain, and post-exercise muscle soreness. The mineral content — particularly sulfate and magnesium — contributes anti-inflammatory effects beyond what heat alone provides.

Skin Health

Silica-rich and sodium bicarbonate waters are particularly notable for skin effects. Silica stimulates collagen synthesis and improves skin elasticity. Bicarbonate water's alkalinity gently exfoliates and leaves skin unusually soft. Sulfur has long been used topically for conditions including eczema and psoriasis. Many regular soakers report dramatic improvements in skin texture and hydration.

What to Expect on
Your First Visit

First-time hot spring visitors often feel slightly disoriented — not because the experience is complicated, but because it operates on a different pace than most modern leisure activities. There's nothing to do. No screen, no task, no goal. Just water, minerals, heat, and time. Here's what to expect so you can settle in rather than feel lost.

Arrival & Check-In

Most developed hot springs resorts operate like a day spa — you pay an entry fee (typically $20–$60 depending on the facility), receive a wristband or locker key, and change in a locker room. You'll typically have access to multiple pools at different temperatures. Some facilities provide towels; others require you to bring your own. Check the specific facility's website before you go.

The Pool Temperatures

Most facilities offer multiple pools at different temperatures — usually ranging from a warm pool around 98°F to a hot pool at 104–108°F or higher. Always start in a cooler pool first. Give your body 5–10 minutes to acclimate before moving to hotter water. The hottest pools are not "better" — they're simply different, and hotter water carries more risk if you jump in too quickly.

The Sensation

Mineral-rich water feels noticeably different from a heated pool or hot tub. It's often silkier, sometimes slightly slippery on the skin. You may feel a slight tingle, particularly from sulfate-rich or bicarbonate-rich water. The buoyancy feels different. And after 15–20 minutes, you'll likely feel a deep, full-body relaxation that's qualitatively different from what a jacuzzi produces.

The Time Distortion

One of the most universally reported hot spring phenomena: time moves differently in the water. Conversations go deeper. Silence becomes comfortable. The usual mental chatter slows down. This is partly the parasympathetic nervous system response, partly the absence of screens, and partly something harder to measure. Lean into it. This is the point.

How to Soak:
The Complete Protocol

There is no single "correct" way to use a hot spring — the practice is deeply personal and varies by culture. But there are evidence-based principles that will help you get the most from the experience physically, while also building a ritual that becomes richer over time.

Before You Arrive

• Hydrate aggressively. Drink at least 16–24 oz of water before you get in. Thermal soaking is dehydrating — the heat causes you to sweat even while submerged, and you lose more fluid than you realize.
• Skip sunscreen. Most mineral springs ask you not to apply sunscreen before entering — it introduces chemicals into water that other guests share. Apply after soaking if you're in the sun.
• Eat lightly. A heavy meal before soaking increases cardiovascular strain in the heat. Eat something light 1–2 hours before, or plan to eat after.
• Leave the perfume. Strong fragrances are inconsiderate to other soakers and contaminate the water chemistry. The mineral water has its own scent — part of the experience.

The 20/10 Interval Protocol

The most effective and sustainable soaking method — used by experienced bathers and supported by hydrotherapy research — is the interval approach:

After Your Soak

• Don't shower immediately. Let the minerals stay on your skin for 30–60 minutes after soaking. They continue working as the water evaporates.
• Rehydrate. Drink water with electrolytes — not alcohol. Your body has lost sodium, potassium, and magnesium through sweating.
• Rest. Many people feel deeply sleepy after a mineral soak. This is your parasympathetic nervous system doing exactly what it should. If you can nap — nap.
• Notice the next 24 hours. The effects of a quality mineral soak often continue to develop overnight. Skin feels better the next morning. Sleep quality improves. Muscle soreness resolves.

Hot Springs Etiquette

Hot spring culture has its own code — unwritten in most places but deeply felt by regular soakers. Respecting the water and the community around it is what separates a tourist from a soaker. Here are the rules that matter most:

• Shower before entering. Always. Without exception. You're sharing mineral water with dozens of other people. Removing body products, sunscreen, and environmental pollutants before entering protects the water chemistry and respects your fellow soakers.
• No phones in the pool. This is near-universal at quality hot springs. The pools are a screen-free zone. Honor it. You can take photos from the deck.
• Speak quietly. Hot springs are restorative spaces. Loud conversations, music, or disruptive behavior break the collective experience. Match the energy of the space.
• No sunscreen, lotions, or products in the water. These chemicals alter the mineral balance and are unfair to other bathers. Apply products after you're done soaking.
• Read the clothing optional rules. Some springs are clothing optional; others require swimwear; others have designated CO areas. Know the rules before you arrive — and respect whatever they are.
• Don't monopolize space. In busy pools, be mindful of how much space you occupy. Move if someone clearly needs room. Share the experience.
• Leave no trace at primitive springs. Carry out everything you bring in. Don't introduce soaps, shampoos, or food into natural hot springs. These are living ecosystems.
• Respect the silence. Many soakers are there for a deep quiet experience. You don't have to be silent — but you should read the room.

What to Bring

Packing for a hot springs visit is simple once you know the essentials. Here's the complete list:

The Essentials

• Swimsuit — quick-dry fabric recommended. Dark colors hide mineral staining.
• Large absorbent towel — or two. Microfiber towels dry faster; Turkish towels are compact and stylish.
• Water bottle — 32 oz minimum. You will need it.
• Electrolytes — LMNT, Liquid IV, or similar. Mix into your water before and after soaking.
• Flip flops / sandals — for walking between pools and locker rooms.
• Change of clothes — mineral water leaves a distinct smell on swimwear. Have dry clothes for the drive home.
• Cash — many smaller springs are cash-only for entry fees.

Nice to Have

• Robe — for the rest periods between soaks. Patagonia and Pendleton make excellent options.
• Small dry bag — to keep your phone and valuables dry on the pool deck.
• Light snack — fruit, nuts, or a light bar for energy after your soak.
• Hair tie / clip — mineral water affects hair differently than chlorinated pool water. Keeping hair up protects it.
• Journal — many people find the reflective state induced by mineral soaking is excellent for thinking and writing.

Leave at Home

• Sunscreen (apply before leaving home, not at the spring)
• Heavy perfume or cologne
• Bluetooth speaker (seriously)
• Alcohol (most facilities prohibit it in the pool area)

Types of Hot Springs:
Resort vs. Primitive

American hot springs exist on a wide spectrum from full-service luxury resorts to completely undeveloped wilderness pools. Understanding the difference will help you choose the right experience for where you are in your soaking journey.

Developed Resorts

Full-service hot springs resorts like The Springs Resort in Pagosa Springs or Chena Hot Springs in Alaska offer the complete package: professionally managed pools, consistent water quality testing, locker rooms, towel service, food and beverage, spa treatments, and on-site lodging. The mineral water is still entirely natural and geothermal — the resort simply provides infrastructure around it. Entry fees are typically $30–$80 per day. Ideal for first-timers and those who want a curated, comfortable experience.

Primitive Hot Springs

At the other end of the spectrum are primitive springs — natural pools on public land (National Forests, BLM land) with no infrastructure whatsoever. Many are free. Some require a hike. You bring everything and take everything out. The water quality testing happens nowhere — you're soaking in truly wild geothermal water. The experience is incomparably raw and often more beautiful than anything a resort can offer. Idaho's Goldbug Hot Springs, Oregon's Umpqua Hot Springs, and California's Fifth Water are examples of primitive springs that rival any resort in the world for sheer beauty.

Which Should You Choose First?

For your first hot spring experience, a developed resort is the better starting point. You'll have proper facilities, temperature-tested pools, staff on site, and a structured environment to learn what you enjoy. Once you know what kind of soaker you are — how hot you like it, how long you want to stay, whether you want silence or community — you'll be better equipped to navigate the more adventurous primitive options.

How to Find
Hot Springs Near You

The United States has over 500 documented hot springs across more than 30 states — from the obvious geothermal hot zones of the American West to surprising finds in Arkansas, Virginia, and New York. Here's how to find the best ones:

Use the Geothermal Lifestyle Hot Springs Guide

We've done the work for you. Our complete Hot Springs by State guide covers every major geothermal destination in America — with temperatures, mineral profiles, ratings, and the information you need to plan a trip. It's the most comprehensive free resource of its kind.

Download the Hot Springs Passport

Our free Hot Springs Passport app lets you track every spring you visit, discover new ones nearby, and build a lifetime soaking record. It covers 500+ springs nationwide and is the best planning tool available for serious soakers.

The Best Hot Springs Regions in America

• Colorado Hot Springs Loop — 23 facilities across 800 miles of mountain scenery. The most concentrated high-quality hot springs corridor in North America.
• Idaho's backcountry — more primitive hot springs per capita than any other state. Goldbug, Kirkham, Burgdorf, and dozens more.
• Oregon's Cascade Range — world-class resort experiences (Breitenbush) and stunning primitive pools (Umpqua, Bagby) in old-growth forest.
• New Mexico's high desert — Ojo Caliente, Ten Thousand Waves, and Spence Hot Springs in a landscape unlike anywhere else in the country.
• Montana's wilderness springs — Chico, Quinn's, and the incomparable Boiling River inside Yellowstone National Park.
• Alaska's last frontier — Chena Hot Springs with the Northern Lights, and remote fly-in wilderness springs that few people ever see.

A Final Word

There is a reason every ancient civilization that had access to thermal mineral water built culture around it. Roman baths. Japanese onsen. Turkish hammam. Icelandic pools. The therapeutic, communal, and spiritual dimensions of soaking in naturally heated mineral water are not trends — they are among the oldest continuous human practices on earth.

The modern American hot springs movement is not a wellness fad. It is a rediscovery. And now that you understand the geology, the chemistry, the protocol, and the culture — you're ready to be part of it.