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Spa town
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A spa town is a resort town based on a mineral spa (a developed mineral spring). Patrons may visit spas to "take the waters" for their purported health benefits.
Thomas Guidott set up a medical practice in the English town of Bath in 1668. He became interested in the curative properties of the hot mineral waters there and in 1676 wrote A discourse of Bathe, and the hot waters there. Also, Some Enquiries into the Nature of the water. This brought the purported health-giving properties of the waters to the attention of the aristocracy, who started to partake in them soon after.[1]
The term spa is used for towns or resorts offering hydrotherapy, which can include cold water or mineral water treatments and geothermal baths, and comes from the Belgian town Spa.[2]
Spa towns by country
[edit]Argentina
[edit]Australia
[edit]There are mineral springs in the Central Highlands of Victoria. Most are in and around Daylesford and Hepburn Springs.[3] Daylesford and Hepburn Springs call themselves "Spa Country" and the "Spa Centre of Australia".
In Queensland, many towns have mineral springs created by artesian bores into the Great Artesian Basin, often the only or primary water supply to the towns. Some of these towns had periods of popularity as spa towns, including Ararmac, Barcaldine, Dalby, Helidon, Innot Hot Springs, and Muckadilla, mostly in the late 1800s and early 1900s when mineral spas were believed to cure various medical conditions. However, the remote locations of most of these towns made them expensive to visit and only small-scale spa facilities developed there. Helidon, a day trip from Brisbane by car, was more successful, particularly with growing ownership of cars after World War II. However, concerns about radioactivity and bacterial contamination resulted in the Helidon Spa falling into disuse by 1994. Many towns in Queensland continue to provide bathing facilities fed by hot springs, but these are promoted as relaxing holiday activities rather than as medical treatments.[4]
Belgium
[edit]- Chaudfontaine (lit. "hot fountain" in French)
- Ostend
- Spa (the eponym for the modern word)
Bosnia and Herzegovina
[edit]
- Banja Ilidža, a spa town near capital Sarajevo
- Banja Slatina, Slatina - Slatina is a spa town, well-known as one of the best health resorts for rheumatism in the region. Slatina has a tradition since 1870s.
- Banja Vrućica, Teslić
Brazil
[edit]Brazil has a growing number of spa towns. The traditional ones are: Águas de Lindoia, Serra Negra, Águas de São Pedro, Caxambu, Poços de Caldas, Caldas Novas, Araxá, and São Lourenço.
Bulgaria
[edit]Bulgaria is known for its more than 500 mineral springs, including the hottest spring in the Balkans at Sapareva Banya - 103 °C. Other famous spa towns include Sandanski, Hisarya, Bankya, Devin, Kyustendil, Varshets, Velingrad.
In Bulgarian, the word for a spa is баня (transliterated banya).
Canada
[edit]Harrison Hot Springs is one of the oldest among 18 in British Columbia; there are also two in Alberta and one in Ontario.
Croatia
[edit]In Croatia, the word Toplice implies a spa town. The most famous spa towns in Croatia are Daruvar, Šibenik and Sisak.
Czech Republic
[edit]
In Czech, the word Lázně implies a spa town. The most famous spa towns in Czech Republic are the West Bohemian Spa Triangle of Karlovy Vary, Františkovy Lázně and Mariánské Lázně, listed on UNESCO World Heritage Site. Other important spas are Luhačovice, Teplice, Jáchymov, Konstantinovy Lázně, Jeseník, Třeboň, Poděbrady, Bechyně or Velké Losiny.
Finland
[edit]Traditionally, Hanko,[5] Rauma[6] and Kalajoki have been considered spa towns. Today there are more than 50 spas (kylpylä) in Finland;[7] some towns known for their spa centers include Ikaalinen, Naantali and Imatra.
France
[edit]In France, the words bains, thermes and eaux in city names often imply a spa town. There are more than 50 spa towns in France, including Vichy, Aix-les-Bains, Bagnoles-de-l'Orne, Dax, and Enghien-les-Bains.
Georgia
[edit]Borjomi is one such example in south Georgia.
Germany
[edit]In Germany, the word Bad implies a spa (bath) town. It is also referred to as a "kurort" - a place for curing. Among the many famous spa towns in Germany are Bad Aachen, Baden-Baden, Bad Brückenau, Bad Ems, Bad Homburg, Bad Honnef, Bad Kissingen, Bad Kreuznach, Bad Mergentheim, Bad Muskau, Bad Oeynhausen, Bad Pyrmont, Bad Reichenhall, Bad Saarow, Bad Schandau, Bad Schönborn, Bad Segeberg, Bad Soden, Bad Tölz, Bad Wildbad, Bad Wimpfen, Bad Wildstein, Berchtesgaden, Binz, Freudenstadt, Heiligendamm, Heringsdorf, Kampen, Königstein, Radebeul, Schwangau, St. Blasien, Titisee, Tegernsee, Travemünde and Zingst. Wiesbaden is the largest spa town in Germany.
Greece
[edit]The most popular spa towns in Greece are Aidipsos, Agkistro, Serres, Loutraki, Kamena Vourla, Kimolos, Loutra Kyllinis, Sidirokastro, Serres, Lakkos Milos, Loutrochori, Aridaia, Pella (Pozar)
Hungary
[edit]In Hungary, the word fürdő or the more archaic füred ("bath"), fürdőváros ("spa town") or fürdőhely ("bathing place") implies a spa town. Hungary is rich in thermal waters with purported health benefits, and many spa towns are popular tourist destinations. Budapest has several spas, including Turkish style spas dating back to the 16th century. Eger also has a Turkish spa. Other famous spas include the ones at Hévíz, Harkány, Bük, Hajdúszoboszló, Gyula, Bogács, Bükkszék, Zalakaros, the Cave Bath at Miskolctapolca and the Zsóry-fürdő at Mezőkövesd.
India
[edit]Indonesia
[edit]Italy
[edit]
In Italy, spa towns, called città termale (from Latin thermae), are very numerous all over the country because of the intense geological activity of the territory. These places were known and used since the Roman age.
Iraq
[edit]Japan
[edit]Kazakhstan
[edit]- Burabay, lies in the Kokshetau Mountains, part of the Kokshetau Hills of the Kazakh Uplands (Saryarka).
Luxembourg
[edit]Lithuania
[edit]- Druskininkai - is known for mineral springs. The name comes from Lithuanian word druska - salt.
- Birštonas - is known for mineral springs and curative mud applications.
Netherlands
[edit]- Bad Nieuweschans in the North on the border with Germany, with "Bad" implying a spa town.
- Valkenburg near Maastricht, which wants to be a "city of wellness".
New Zealand
[edit]- Rotorua
- Hanmer Springs
- Waiwera
- Te Aroha

Te Aroha Hot Springs Domain - Ngawha Springs
- Te Aroha Hot Springs Domain
Poland
[edit]Most spa towns in Poland are located in the Lesser Poland and Lower Silesian Voivodeships. Some of them have an affix "Zdrój" in their name (written with hyphen or separately), meaning "water spring", to denote their spa status, but this is not a general rule (e.g. Ciechocinek and Inowrocław are spa towns, but do not use the affix).
Portugal
[edit]
Portugal is well known by famous spa towns throughout of the country.
Due to its high quality, as well as the landscape where are located, the most important ones are:
- Caldas da Rainha
- Caldas das Taipas
- Caldas de Monchique
- Termas do Gerês
- Caldas de Vizela
- Pedras Salgadas
- Vidago
- Chaves
- São Pedro do Sul
- Caldas da Felgueira located in Viseu District, and 5km from Nelas town.
- Termas de Monfortinho
- Caldas de São Jorge
Romania
[edit]In Romania, the word Băile implies a spa town. The most famous spa towns in Romania are Băile Herculane, Băile Felix, Mangalia, Covasna, Călimănești & Borsec.
Serbia
[edit]Serbia is known for its many spa cities. Some of the best known springs are the Vrnjačka Banja, Bukovička Banja, Vrujci, Sokobanja and Niška Banja. The hottest spring in Serbia is at Vranjska Banja (96°C)[8]
In Serbia, the word Banja implies a spa town.
Slovakia
[edit]
Slovakia is well known by its spa towns. The most famous is the city of Piešťany in Trnava Region. Other notable spa towns in Slovakia include:
- Bardejov
- Brusno
- Bojnice
- Číž
- Dudince
- Liptovský Ján
- Lúčky
- Piešťany
- Rajecké Teplice
- Sklené Teplice
- Sliač
- Smrdáky
- Trenčianske Teplice
- Turčianske Teplice
Slovenia
[edit]Spa towns in Slovenia include Rogaška Slatina, Radenci, Čatež ob Savi, Dobrna, Dolenjske Toplice, Šmarješke Toplice, Moravske Toplice, Rimske Toplice, Laško and Topolšica. They offer accommodation in hotels, apartments, bungalows, and camp sites. The Slovenian words terme or toplice imply a spa town.
South Africa
[edit]Spa towns in South Africa include:
South Korea(한국, 남한)
[edit]
Spain
[edit]Spa towns in Spain include:
- Alhama de Aragon
- Panticosa in the high Pyrenees
- Archena
- Caldes d'Estrac
- Caldes de Montbui
- Riofrío
- Caldes de Malavella
- Lanjarón
- A Toxa, an island-spa in northwestern Galicia.
- Mondariz
- Arnedillo
- Zestoa
- Karrantza
- Montemayor
- Caldas de Luna
Sweden
[edit]- Ramlösa now a part of Helsingborg
Switzerland
[edit]- Baden
- Bad Ragaz (Ragatz, also known as "Old Baths Pfäfers" or "Old Baths of Pfäfersin")
- Davos
- Lavey-les-Bains
- Leukerbad
- Schinznach Bad
- Yverdon-les-Bains
- Zurzach
- Ragatz
Taiwan
[edit]
Taiwan is home to a number of towns and cities with tourism infrastructure centered on hot springs. These include:
- Jiaoxi, Yilan
- Wulai, New Taipei
- Beitou District, Taipei City
- Tai'an, Miaoli
- Guguan, in Heping, Taichung
Tunisia
[edit]There are several spa tonws in Tunisia:
Turkey
[edit]There are several spa towns in Turkey. The most famous of these is Pamukkale, Denizli where the Pamukkale thermal springs are located.
Ukraine
[edit]United Kingdom
[edit]Some but not all UK spa towns contain "Spa", "Wells", or "Bath" in their names, e.g., Matlock Bath. Some towns are designated Spa Heritage Towns. Two out of four of the English towns granted the title "Royal", Royal Leamington Spa and Royal Tunbridge Wells, are spa towns.
United States
[edit]- Chena Hot Springs, Alaska
- Eureka Springs, Arkansas
- Hot Springs, Arkansas
- Calistoga, California
- Desert Hot Springs, California
- Palm Springs, California
- Glenwood Springs, Colorado
- Pagosa Springs, Colorado
- Steamboat Springs, Colorado
- Safety Harbor, Florida
- Warm Springs, Georgia
- Lava Hot Springs, Idaho
- West Baden Springs, Indiana
- Mount Clemens, Michigan
- Excelsior Springs, Missouri
- Jemez Springs, New Mexico
- Truth or Consequences, New Mexico
- Gila Hot Springs, New Mexico
- Ballston Spa, New York
- Saratoga Springs, New York
- Hot Springs, North Carolina
- Bedford, Pennsylvania
- Hot Springs, South Dakota
- Mineral Wells, Texas
- Warm Springs, Virginia
- Connell, Washington
- Bath (Berkeley Springs), West Virginia
- Waukesha, Wisconsin
- Saratoga, Wyoming
- Thermopolis, Wyoming
Terminology
[edit]Terms used in various countries:
- in the Arab world - Hammam
- in Bulgaria - Bani
- in Chile - Termas
- in Croatia - Toplice
- in Cyprus - Loutra-Therma
- in the Czech Republic - Lázně
- in Ethiopia - Filwoha
- in France - Bains, thermes
- in Georgia - სამკურნალო წყლები
- in Germany, Austria, and Switzerland - Bad, the first part of the names of most spa towns, a cognate to the English "bath" while "Therme" is used for the spa itself.
- in Greece - Loutra-Therma
- in Hungary - fürdő or -füred
- in Italy - Terme
- in Iran - Cheshme Ab-e-Garm" or "Cheshme Ab-e-Madani
- in Japan - Onsen
- in Korea - 온천
- in Mexico- Termas or Balneario
- in Peru - Cuzco, Cajamarca
- in Poland - List of spa towns in Poland
- in Portugal - Caldas or Termas
- in Russia - Минеральные воды or Лечебные воды
- in Romania - Băile
- in Slovakia - Liečebné kúpele
- in Serbia - Banja
- in Spain - Termas or Balneario
- in Turkey - Termal or Kaplica
- in Ukraine - Лікувальні води
See also
[edit]- Spa
- Resort architecture
- Spa architecture
- Spa resort
- Hot spring
- Sauna
- Thermae
- Mineral water
- Hydrotherapy
- Sanatorium
- Great Spas of Europe, UNESCO World Heritage site
References
[edit]- ^ Burns, D. Thorburn (1981). "Thomas Guidott (1638–1705): Physician and Chymist, contributor to the analysis of mineral waters". Analytical Proceedings. 18 (1): 2–6. doi:10.1039/AP9811800002.
- ^ "Healing Waters; Investigative Files (Skeptical Briefs June 2005)". Archived from the original on 24 October 2007. Retrieved 3 February 2008.
- ^ "VICTORIAN MINERAL SPRINGS: STRATEGIC MASTERPLAN 2015-2024". Victorian Mineral Water Committee. p. 3.
- ^ Griggs, Peter (2013). ""Taking the waters": mineral springs, artesian bores and health tourism in Queensland, 1870-1950" (PDF). Queensland Review. 20 (2). Cambridge University Press: 157–158, 169. doi:10.1017/qre.2013.18. S2CID 39508107. Archived (PDF) from the original on 21 September 2017. Retrieved 20 July 2022.
- ^ "Hangon kylpyläkulttuuri herää henkiin kymmenien vuosien hiljaiselon jälkeen". 16 February 2017.
- ^ "Tiesitkö: Rauma oli huikean suosittu kylpyläkaupunki jo 1700-luvulla". 4 September 2014.
- ^ "Katso lista kaikista Suomen kylpylöistä – mukana myös kartta". 21 September 2017.
- ^ "Reservoir Capital Corp.: 20MW Potential Estimated for the Vranjska Banja Geothermal Project". 23 January 2012. Retrieved 3 February 2012.
Spa town
View on GrokipediaDefinition and Characteristics
Core Definition
A spa town is a resort town or city that has developed primarily around natural mineral springs, hot springs, or geothermal waters, which are harnessed for bathing, drinking, or therapeutic treatments, forming the core of its economic and cultural identity.[5][3] These waters, often rich in minerals, serve as the central attraction, drawing visitors seeking health benefits through balneotherapy and related practices.[6][7] Spa towns differ from general resorts, which prioritize leisure, recreation, and entertainment without a mandatory focus on natural therapeutic waters, as spa towns are intrinsically tied to the medicinal and restorative qualities of their springs.[5] In contrast, broader health resorts may include diverse wellness facilities beyond water-based therapies, such as exercise programs or alternative medicines, whereas spa towns emphasize the unique properties of their geothermal or mineral sources as the foundational element.[8] Certain spa towns gain legal or official recognition to preserve their heritage and resources, including UNESCO World Heritage designation for outstanding examples that exemplify the integration of mineral water use with urban planning and architecture, as seen in the transnational Great Spa Towns of Europe site.[3] National protections, such as state-recognized status in countries like Germany for towns with verified mineral springs, ensure the safeguarding of these waters and associated infrastructure against overexploitation or development threats.[9][10]Key Features and Types
Spa towns are distinguished by their central physical features, primarily natural springs of thermal, mineral, or sulfurous waters that emerge from the earth and form the nucleus of the settlement. These springs are typically enclosed or channeled into bathhouses for immersion therapies and pump rooms equipped with colonnades or fountains for controlled drinking of the mineral-rich waters. Surrounding these sources are landscaped parks and gardens, designed with walking paths, greenery, and recreational spaces to promote relaxation and physical activity in a therapeutic setting.[3][11] Infrastructurally, spa towns integrate amenities tailored to health and leisure, including grand hotels and villas for accommodating visitors, casinos and assembly rooms for social gatherings, and wide promenades lined with shops and cafes to facilitate leisurely strolls. Medical facilities, such as diagnostic centers and treatment halls, are embedded within the town layout, often connected by specialized water piping systems to distribute spring water efficiently for bathing, inhalation, or drinking. These elements create a self-contained urban environment focused on wellness tourism.[3] Spa towns are classified into subtypes based on their primary natural resources and treatment modalities. Thermal spa towns center on hot mineral springs for bathing and heat-based therapies, leveraging geothermal waters above body temperature. Brine spa towns employ highly saline waters, often from salt lakes or evaporated seawater, for osmotic and anti-inflammatory treatments. Mud spa towns utilize peloids—therapeutic clays, volcanic ash, or peat mixed with mineral waters—for applications in packs and baths targeting skin and joint conditions.[11][12][9] The urban planning of spa towns emphasizes a radial or linear design oriented around the springs, with public buildings and pathways converging on these core sites to foster communal health rituals. Architectural styles commonly include neoclassical elements for grandeur and symmetry in pump rooms and bathhouses, alongside Art Nouveau flourishes in facades, ironwork, and decorative motifs that evoke fluidity and nature, reflecting the era's wellness ideals from the 18th to early 20th centuries.[3][13]Historical Development
Ancient and Medieval Periods
The practice of utilizing natural hot springs for therapeutic, hygienic, and social purposes originated in ancient Greece, where thermal waters were integrated into medical traditions. The Sanctuary of Asclepius at Epidaurus, established around the 5th century BCE, functioned as one of the earliest organized sanatoria, employing hydrotherapy through baths and purification rituals to treat ailments, drawing on the healing properties attributed to the site's mild climate and springs.[14] This approach, advanced by figures like Hippocrates (c. 460–375 BCE), emphasized bathing for conditions such as rheumatism and skin disorders, influencing over 400 similar Asclepieia across the Greek world.[14] The Romans systematized and expanded these traditions, constructing balneae (modest public baths) and grander thermae complexes that served as multifunctional hubs for cleansing, medical treatment, exercise, and socialization. By the late Republic, around 170 such facilities dotted Rome alone, with thermae like those of Agrippa (built c. 19 BCE) and later emperors incorporating art, libraries, and heated pools over natural springs.[15] These structures proliferated across the empire via extensive road networks, promoting Roman cultural assimilation; a key example is Aquae (modern Baden-Baden, Germany), where 2nd-century CE baths treated soldiers' injuries with thermal waters, reflecting both military and civilian uses.[16] Roman baths emphasized sequential immersion from hot to cold waters, fostering hygiene and community, though access was often segregated by gender and class.[17] Following the Western Roman Empire's collapse in the 5th century CE, large-scale bathing facilities declined sharply due to intertwined economic, infrastructural, and cultural factors. Economic impoverishment reduced funding for maintenance, while aqueduct disruptions from wars, sieges (e.g., Rome in 536 CE), and natural disasters like earthquakes rendered many thermae inoperable, shifting reliance to smaller, bucket-filled baths or private wells.[18] The rise of Christianity further contributed, with ascetic ideals and church canons (e.g., Synod of Laodicea c. 363 CE) discouraging mixed-gender luxury bathing as indulgent, prioritizing spiritual over secular healing, though bathing persisted in adapted forms among the populace.[18] Medieval Europe saw a partial revival of spring-based healing under monastic and feudal auspices, often blending Christian and classical elements. In Bath, England (ancient Aquae Sulis), the hot springs regained prominence from the 12th century under Norman influence, with the Cross Bath constructed in the medieval period as a therapeutic pool sheltered for the infirm, integrated with the nearby abbey for pilgrims seeking relief from ailments.[19] This monastic patronage emphasized waters' curative roles, marking an early feudal adaptation of Roman practices. In the Islamic world, hammams emerged as vital institutions from the Umayyad period (661–750 CE), evolving from Roman and Byzantine models into single-sex public baths that promoted hygiene, social exchange, and therapy through steam and temperature contrasts to stimulate circulation and purify the body.[20] By the Abbasid era (8th–13th centuries), cities like Baghdad hosted thousands of such facilities, underscoring their role in urban health and community life.[20] Beyond Europe and the Middle East, indigenous cultures independently harnessed hot springs in pre-modern contexts. In Japan, onsen precursors date to at least the 8th century CE, with the Nihon Shoki (720 CE) recording therapeutic soaks.[21] In the Americas, pre-Columbian peoples like the Taíno utilized thermal sites such as Baños de Coamo in Puerto Rico for ritual and medicinal bathing, while Native American groups in regions like present-day Hot Springs National Park, Arkansas, frequented springs for thousands of years, incorporating them into healing traditions alongside resource gathering.[22] These practices highlight a global, pre-industrial recognition of thermal waters' benefits, predating formalized spa towns.[22]Modern Era and Global Expansion
The resurgence of spa towns in the 18th and 19th centuries coincided with the Grand Tour, a customary educational journey undertaken by European aristocracy that often included visits to renowned thermal destinations for health and leisure.[23] The town of Spa in Belgium, from which the term "spa" derives, emerged as a premier aristocratic retreat during this era, attracting elite travelers seeking the purported curative properties of its mineral springs.[24] Similarly, Karlovy Vary (formerly Karlsbad) in the Czech Republic flourished as a luxurious spa resort in the 19th century, drawing monarchs and nobility who commissioned grand colonnades and pavilions around its hot springs.[25] Monarchs played a pivotal role in elevating these towns' prestige; for instance, Tsar Peter the Great visited Spa in 1717, where he was reportedly cured of chronic indigestion, subsequently praising its waters and inspiring further royal patronage across Europe.[26] The 19th century marked a pivotal expansion driven by industrial advancements and colonial networks, transforming spa towns from elite enclaves into more accessible tourist hubs. The advent of railways significantly boosted visitation, enabling middle-class travelers to reach remote thermal sites and spurring urban development around bathhouses and promenades in Europe.[27] In colonial contexts, British administrators in India established hill stations such as Shimla and Mussoorie as sanatoriums mimicking European spas, providing respite from the tropical climate and serving as seasonal retreats for the Raj elite.[28] Across the Atlantic, Hot Springs in Arkansas evolved into America's premier spa destination by the 1830s, with log cabins and bath facilities giving way to elegant Victorian-style resorts that catered to health-seeking visitors via expanding rail lines.[22] In the 19th century, regulatory frameworks for spas emerged in Belgium and across Europe, standardizing operations and hygiene to support the growing industry.[29] The 20th and 21st centuries brought challenges and reinvention for spa towns, with post-World War II shifts toward modern medicine causing a decline in traditional medical tourism from the 1930s to the 1980s.[30] Many European spas, once bustling with curative prescriptions, faced abandonment as antibiotics and pharmaceuticals supplanted balneotherapy, leading to the closure of facilities in towns like those in France and the United States.[31] A revival began in the late 20th century, accelerated by UNESCO recognitions such as Bath's inscription as a World Heritage Site in 1987, which highlighted the architectural and cultural legacy of these destinations.[32] Globalization further propelled this resurgence, integrating Asian onsen traditions—such as Japan's geothermal hot springs—into the international wellness market, while eco-spa developments emphasized sustainable practices like adaptive reuse of historic buildings and low-impact water management since the 2000s.[33][34] Today, spa towns blend heritage with contemporary wellness tourism, focusing on holistic health amid growing demand for eco-conscious retreats.[35]Therapeutic and Health Aspects
Mineral Waters and Their Properties
Mineral waters in spa towns originate from deep aquifers influenced by geological processes such as tectonic activity and volcanic sources, where rainwater infiltrates permeable rock layers and circulates through faults and fractures, acquiring heat and dissolved minerals over extended periods.[14] These waters become thermal when their temperature exceeds 20°C upon emergence, often due to geothermal gradients in tectonically active regions, resulting in types such as bicarbonate waters from limestone dissolution, sulfur waters from volcanic gases, and radon waters from uranium-rich granitic rocks.[36] Aquifers in areas like the Pannonian Basin or the Alps exemplify this formation, where intensive tectonic stress enhances mineral enrichment.[37] The chemical composition of these waters features key minerals including calcium, magnesium, sodium, potassium, bicarbonates, sulfates, and chlorides, with concentrations varying by source rock interactions.[38] Total dissolved solids (TDS), a measure of overall mineral content, typically range from 500 to over 5,000 mg/L in spa waters, distinguishing them from low-mineral freshwater.[39] For instance, calcium and magnesium levels often exceed 100 mg/L each in hard waters from carbonate aquifers, while sodium can reach 1,000 mg/L in evaporite-influenced springs.[40] Balneological classification systems categorize these waters based on temperature, pH, and mineral content to standardize their properties. Waters are grouped by temperature as cold (below 20°C), hypothermal (20–35°C), or hyperthermal (above 35°C); by pH as acidic (below 7) or alkaline (above 7); and by dominant ions, such as bicarbonate waters exceeding 600 mg/L or sulfate waters over 200 mg/L.[39]| Classification Criterion | Categories and Thresholds |
|---|---|
| Temperature | Cold: <20°C; Hypothermal: 20–35°C; Hyperthermal: >35°C[39] |
| pH | Acidic: <7; Alkaline: >7[39] |
| Mineral Content (examples) | Bicarbonate: >600 mg/L; Sulfate: >200 mg/L; Oligomineral: <50 mg/L TDS[39] |

