In 1924 the town of Hajdúszoboszló, in eastern Hungary, gave the geologist Ferenc Pávai-Vajna and the geophysicist Dezső Pekár permission to look for natural gas. On 26 October 1925 their well, just over a kilometre deep, found gas and, with it, hot water. Hungarian Wikipedia gives the date and the names. The operator of Hungarospa Hajdúszoboszló tells it as a search for oil and quotes two doctors on the result. János Bodnár of the medical chemistry department in Debrecen classed it as an alkaline, iodine- and bromine-bearing thermal water. Zoltán Dalmady called it something like seawater diluted five times, "the summoned spirit of a Triassic sea".
Sand baths were ready by July 1927. In 1934, according to Hungarian Wikipedia, the minister of the interior declared the bath at Hajdúszoboszló a gyógyfürdő, a medicinal bath. That last step is the subject of this piece. Any spa can call its water healing. The legal words, gyógyvíz in Hungary, Heilquelle in Germany, léčivý zdroj in Czechia, are given by an office, about one spring at a time, and every country has built a different office for it. 239 baths state that they use water with such a designation.
Our piece on thermal, mineral and medicinal explains how the three words differ. This one is about the paperwork: who signs, what they ask for, and what a few named baths went through.
Who decides that a spring is medicinal?
A public authority, never the bath. What it decides is narrower than it sounds: that this source, at this well, has a known and stable composition that meets a legal definition, and that it may be used in a stated way. The answers differ in the detail, and the detail is where the differences between countries show.
Hungary: a laboratory report less than a year old
Under a government decree of 2023 on natural healing factors, a Hungarian water may carry a name that refers to a healing effect only with the permission of the Government Office of Budapest. The national public health centre, the NNGYK, gives its expert opinion in every case: whether the water is for bathing or for drinking, under what restrictions, and what treatment it may undergo. Its guidance for applicants is specific. The file needs a full analysis, microbiological, chemical and radiological, from an accredited laboratory that took the sample on site, and the analysis may not be more than a year old. The application names the well by its cadastral number and states its depth. A bath that disinfects or degasses its water has to submit the analysis of the treated water as well.
One detail tells you a great deal about Hungarian geology. A new well can qualify by analogy, if it lies inside the protection zone of a well that is already recognised, draws from the same aquifer, and its composition matches within the bounds of natural variation, a maximum of 20 per cent. 98 Hungarian baths state that they use water with the designation, more than in any other country.
Germany and Austria: one state at a time
Neither country has a single office for this. In Germany the federal states recognise their own springs. The North Rhine-Westphalia guidelines of 1981 are a good example of what a file contains: a medicinal-water analysis no more than twenty years old, a control analysis if it is older than five, a hygiene report, and a balneological expert opinion on the results of clinical testing, with indications and contraindications. Every five years the regional government has to receive fresh hygiene results. A recognised spring is a staatlich anerkannte Heilquelle, and a town built around one may later be allowed to put Bad in front of its name, which is a separate decision.
Bad Füssing, in Lower Bavaria, shows both steps. Thermal water was found there in 1937–38 during a search for oil. The municipality's spa director, giving evidence to a Bundestag committee in 2024, dates the state recognition to 28 June 1950. Look at the name the water received: a sulphur- and fluoride-bearing sodium-hydrogencarbonate-chloride thermal water. The certificate is a chemical description. The indications, with musculoskeletal conditions first, were set afterwards, and the title Bad came in 1969. Today Therme eins and Europa Therme are two of the town's three public thermal baths. 60 German baths state that they hold a medicinal-water recognition.
In Austria the provincial government recognises a Heilvorkommen, a natural healing resource. Lower Austria's procedure asks the owner of the source for a full analysis and a private expert's report showing that the source has a healing effect recognised by science because of its natural composition, with indications, contraindications and whether the composition needs altering before use. The recognition is published in the province's official gazette. Baden, south of Vienna, is in that province. The Romans called it Aquae, Wikipedia says, and its fourteen springs come up at 22 to 36 °C. At Römertherme Baden the operator fills one pool, the outdoor sulphur basin it calls the traditional Schwefelwandl, with water from Baden's healing springs, at 34–36 °C. For the rest of the country, see our guide to Austria's thermal baths.
Czechia and Slovakia: the ministry, and the ground around the spring
In Czechia the Ministry of Health issues the certificate, the osvědčení, under the Spa Act of 2001, and announces it in the Collection of Laws, the same journal that publishes statutes. Its spa inspectorate keeps the register of natural healing sources and supervises the people who use them.
Why a ministry cares so much becomes clear in Teplice, in the north of Bohemia. On 10 February 1879, the town's tourist office writes, miners at the Döllinger pit near Duchcov broke into hot water. Two days later Pravřídlo, the main spring of the spa, was gone. The whole season was at risk. Experts from Vienna found the spring again by deep drilling and organised drainage and continuous pumping of the mine, and the office says the pumping is still needed today. Lázně Teplice v Čechách bathes in that water now. A certificate protects a source as well as describing it. That is what the protection zones drawn around each recognised spring are for.
Slovakia draws them in law. A 2000 decree of the Ministry of Health set the protection zones for the healing sources of Bardejov: an inner zone around the outflow, and outer zones reaching across seven cadastral districts. The maps are kept at the ministry's spa inspectorate, at the regional and district offices and at the spa company itself. Bardejovské kúpele, two and a half kilometres north of the town, has had guests including Marie Louise, Napoleon's wife, Tsar Alexander I and the Empress Elisabeth, according to Wikipedia. For the region as a whole there is our guide to the Czech spa towns.
Portugal and Spain: water as a mine
On the Iberian peninsula a medicinal spring is first of all a geological resource. In Spain mineral-medicinal water falls under the Mining Act of 1973, as a "Section B" resource, and the regions declare it. In Andalusia, one such file was received by the mining service in April 2017; the resolution declaring the water mineral-medicinal followed in December 2018 and was published in March 2019. The Balneario de Lanjarón, in the Alpujarra south of Granada, is in the same region and under the same law. Spanish Wikipedia lists six mineral-medicinal springs there, five for drinking and one, El Salado, for bathing, and dates the springs building to 1928.
Portugal splits the job at a door. The thermal sector's own good-practice manual, published by the Associação das Termas de Portugal, explains that the water is supervised by the mines and energy directorate, the DGEG, as far as the entrance of the bath house, and is the responsibility of a technical director up to that point. From the threshold on, the clinical director answers for it, and the therapeutic uses are the ones the Directorate-General of Health has recognised. The best-known story begins with a queen. In 1484, Wikipedia records, Queen Leonor, travelling from Óbidos to Batalha, came upon peasants bathing in foul-smelling water by the road; she ordered a hospital built, work began the next year, and the first patients came in 1488. The town became Caldas da Rainha, the Queen's hot springs, and the baths there today are Termas da Rainha. 35 Portuguese baths use water recognised as mineral-medicinal.
Does a certified water mean the water will help you?
It means the water is what the bath says it is. None of these procedures promises an effect on a particular person. The German and Austrian files contain indications and contraindications, but they are the expert's statements attached to a recognition, and the list a bath publishes is the operator's own.
Read the list of who should stay out of the water as carefully as the list of what it is for. Hungarospa states that its water is not recommended for people with acute inflammatory illness, any form of cancer, circulatory disorders, severe high blood pressure, tuberculosis or serious disease of the central nervous system, nor during pregnancy. If any of it could apply to you, or you are taking medication, ask your doctor before you book a course of medicinal baths, and take the bath's analysis with you.
How can you check a medicinal-water claim yourself?
Start with the word. Gyógyvíz, Heilquelle, léčivý zdroj, água mineromedicinal and agua minero-medicinal are granted; "healing", "vital" and "wellness" are not. Then ask the bath which authority recognised the source and when. A bath with a real designation can name the office, and often the date: Bad Füssing's is 28 June 1950.
Ask for the analysis itself, not a summary. A proper one lists the constituents in milligrams per litre and carries the name of the laboratory and the sampling date. Hungarospa, for example, publishes 5.5 mg of iodide and 9.8 mg of bromide per litre. Only 19 of the certified baths publish a total mineralisation figure, so this question is often answered at the desk rather than online. The counts in this article follow what national registers and the operators themselves state, which is why Hungary and Portugal, whose national registers are published, look more complete than Germany.
Finally, look at the date. North Rhine-Westphalia's guidelines accept an analysis up to twenty years old; a Hungarian application needs one no older than a year. An old analysis is still a real analysis, but you are reading history.
What happens on a first visit to a certified spa?
That depends on what you came for, a day ticket or a course of treatment. A day ticket usually changes nothing: you are in a thermal bath that happens to have certified water, and the house rules apply. In Bad Füssing the municipality gives the medically recommended time in the thermal exercise pool as twenty minutes at most.
A course of treatment starts with a doctor. Portuguese baths are organised around it: the good-practice manual asks the reception to book the medical consultation at the moment you are admitted, and to tell you in writing what stages you will pass through before treatment begins. A spa doctor and your own doctor are the people to ask what the water might do for you; the ticket desk is not.
Whichever country you are in, the certificate behind the word is a public document with an author, a date and a number. Hajdúszoboszló's goes back to a minister's declaration of 1934, Bad Füssing's to a June day in 1950. It is worth asking to see it. Our guides to Hungary and Germany name the baths that use it.