The Croizat hot spring in Mont-Dore, Auvergne
- Nature Source Chaude
- Published on
- Mis à jour le 27 May 2025
The commune of Mont-Dore, located in the Puy-de-Dôme department, boasts an abundance of thermal springs and attractions designed to keep guests at its renowned spa resort happy. However, people have been visiting this area since ancient times. The Romans, who were fond of hot baths, left behind numerous Gallo-Roman artefacts in the park and at the location of the current spa.
The commune also has thermal springs that are no longer used by their owners. The Croizat spring, for example, is located around three kilometres from the Mont-Dore thermal baths and has been abandoned. It belongs to the commune of La Bourboule, whose spa establishments are located just over three kilometres away. Are you following? It would be easier to understand if you looked at the map below.
In this article, I invite you to explore the spring that flows freely between the two major spa resorts.
Table of Contents
Le Sentier des sources
The easiest way to reach the Croizat spring is to start at the Taillerie du Sancy car park and follow the path. This route is quick and straightforward.
From the car park, walk past La Taillerie and follow the road for around 50 metres. A path on the right will then lead you down to the Moulin de la Compissade micro-hydroelectric power station.
To the right of the building, there is a wooden bridge spanning the Dordogne River which provides access to the Sentier des Sources trail (Springs trail).
The trail rises gently for a few dozen metres along the hillside. As it is quite wide, there is no need to wind your way through rocks or along precipices to reach the hot spring.
It is also one of the most accessible hot springs in France. While this increases visitor numbers, it also poses risks to both the environment and people. This was highlighted in a municipal decree issued by the Mont-Dore municipality in 2016, which banned bathing.
After walking up the path for a few dozen metres, I stopped. I found myself next to a narrow, sloping path devoid of trees. Below, I could see a crystal-clear river lined with vegetation. Keen-eyed observers will also spot two nearby pools.
Further on, I came to a fork in the path. Taking the path on the right allows you to walk alongside the river through peaceful surroundings. The Félix spring is less than 500 metres away.
However, if you go left, you will reach a second car park on the side of the road that connects Mont-Dore to La Bourboule.
The pavilion housing the Félix spring is in a state of advanced disrepair and is no longer accessible.
It is actually private property that used to belong to the thermal baths in Mont-Dore. It is now owned by the General Council of the department.
This spring was discovered in 1895 and, at the time, water gushed from it at a temperature of 30°C with a mineral content of four grams per litre. A six-metre-deep borehole was quickly drilled to exploit the spring. However, with a flow rate of just 14 litres per minute, it was not suitable for industrial use. Spa guests bathed in zinc bathtubs near the catchment point.
Unfortunately, the construction of the thermal pavilion was unsuccessful. It did not cater adequately for bathers and was located in an isolated area.
Furthermore, the water temperature (30 degrees at the time, and 19 degrees today) was not suitable for bathing. Therefore, it was necessary to heat it artificially, which was a significant expense at the time.
The site only welcomed around fifty spa visitors per season before being abandoned in the 1930s.
Until recently, people from nearby villages would come here to drink water from the spring beneath this ruined pavilion. It has finally been closed off.
Three rooms can be seen through the blocked-up window, two of which had enough space for one or two bathtubs. In order for men and women to bathe separately at the same time, there needed to be at least two rooms, which appears to be the case here.
The spring is located in the centre of the pavilion. Currently, there is stagnant water on the ground around it (see the iron deposits in the photo), making the sound of flowing water difficult to hear.
From here, you can cross the Dordogne once more via a stone bridge, then climb up to the hamlet of Genestoux.
This spring was formerly named after Mr Chabory, the former director of the thermal baths in Mont-Dore.
The Croizat spring
Despite the heavy rain in recent days, I was surprised at how low the river level was.
However, the two hot water pools on the left bank could flood in the event of heavy rain.
The discovery of natural pools
Relatively far from urban areas, this peaceful spot is the perfect place to escape the hustle and bustle of city life. Although the site is small, it is incredibly meditative. These two hot water pools can accommodate a few bathers in somewhat of a promiscuous setting.
Nevertheless, these two collective pools offer many advantages over a individual pool. Bathers can relax and enjoy the water for as long as they like, as the temperature is kept at 37°C in the first pool and 35°C in the second.
Furthermore, this pleasant temperature is welcome given that prolonged and uninterrupted exposure to these waters is required to treat many conditions.
Finally, all these thermal waters originate from a single source: the Croizat spring. This means that they retain their unique characteristics and thermal properties, as they are not mixed with other thermal waters.
A living medium
With no bathers in the pool, the light highlights the water’s perfect clarity. This light also provides energy for the photosynthetic microorganisms that thrive in the water — there are several billion per litre — as well as for those that cover the pool’s edges.
This thermal plankton (cyanobacteria, protists, etc.) can be seen on the edges of the pool. It produces large quantities of active molecules that disperse in the water.
The same applies to the microorganisms (such as bacteria, archaea and viruses) that inhabit the bottom of the pool. Soil with a certain degree of water retention allows water to percolate through it, providing these microorganisms with nourishment. These microorganisms play a crucial role in maintaining the quality of thermal water and preserving its physical and chemical properties.
The Croizat spring has a partially natural soil (when the site was destroyed, it was covered with concrete, which had to be removed afterwards), providing acceptable living conditions.
Thanks to the presence of microorganisms, which are invisible to the naked eye, and the large quantities of enzymes they produce in the water, the bodily waste (such as hair, dead skin, dirt and sweat) left behind by each person when they soak can be broken down.
Here is some information that may be useful to you:
- However, this fragile ecosystem may be further disrupted by toxic substances, such as those found in cigarettes or certain hygiene products.
- Similarly, piles of stones on the riverbed disrupt the growth of algae and microorganisms, thereby affecting biodiversity.
💡Did you know?
- Each hot spring has its own unique microbiota (i.e. its own microbial ecosystem). Specific flora can also be found in mineral water, whether it is temperate or cold. Consequently, when water is exposed to a degraded environment, the microbiota deteriorates, altering the water’s physical and chemical properties and reducing its therapeutic value. You can find more information on this subject in the article ‘The Soil, Base Layer and Living medium of a Hot Spring‘.
- If the thermal principles are no longer producing the expected effects due to changes in the water, it is the heat of the bath water that provides real benefits to the body. If you would like to find out more, I invite you to read the article: ‘The amazing health benefits of a Hot Bath‘.
A decline in flow rate
Thanks to a flow rate of 100 litres per minute and the pools’ modest size, the water is renewed at a good rate. This is made possible by two short red pipes (see photo above) that limit clogging caused by limescale deposits, sediment and biofilms. They also facilitate the self-cleaning of pools.
However, when it was first discovered around 1900, its flow rate was 200 litres per minute. Since then, this rate has steadily decreased to 100 litres per minute or less today.
It appears that a law of connectedness applies in the case of mineral waters.
There used to be more small thermal springs in Mont-Dore and La Bourboule. However, searching for new springs through digging and drilling (which became widespread in the 19th century) carried the risk of disrupting the flow and temperature of existing ones.
Refrigeration of baths
As for the water from the Croizat spring, it is conveyed through a vaulted gallery buried several metres underground. This gallery is lined with masonry along its entire length (estimated at around 120 metres according to the map).
Once the water has passed through this gallery, it is at the ideal temperature for use in the pool.
This gallery acts as a refrigerator, lowering the temperature of the water.
However, this underground structure can alter the water’s physical and chemical properties. This is because the water flows more slowly through the gallery, changing the conditions in which microorganisms develop.
The gallery was originally used to collect thermal water from a drilled well and drain excess water into the Dordogne River. The well is located on the opposite side of the railway line, in a wooded area.
There is also a ruined thermal building next to the thermal reservoir.
From 1910 onwards, water from the Croizat spring, owned by the Compagnie des Eaux Minérales de la Bourboule (who had purchased it from its inventor, Mr Croizat), was pumped three kilometres to the spa via a cast-iron pipe. The water was then stored in two thermal reservoirs before being transported to the spa establishments in La Bourboule. The spring’s abundant flow was a valuable resource for supplying the baths and showers.
However, the spring became polluted in 1934, when the town of Mont-Dore constructed a water treatment plant less than 600 metres away. This introduced germs, rendering the spring unusable just two years later. This brought an end to its use. The fierce rivalry between the two spa resorts at that time may have contributed to this unusual situation. Furthermore, the inhabitants of Mont-Dore were dissatisfied because the spring’s water emerged on their land before being channelled to the neighbouring spa resort.
In an attempt to avoid surface contamination, drilling continued from the initial 26-metre borehole to a depth of 171 metres in 1938. However, this yielded no significant results. Another borehole was drilled in 1969, this time reaching a depth of 214 metres. However, this caused an underground rockfall and broke the drill bit.
The drill pipe was left behind at the site. This drilling, or previous drilling, has probably affected the flow of the Croizat spring, as well as other nearby springs such as the now-dry petrifying fountain and the Félix spring.
The Croizat spring in old postcards
💧The petrifying spring:
The petrifying spring was located on the left bank of the River Dordogne, close to the Spring of Croizat.
Although it was probably cold, the spring could be used to petrify objects or for therapeutic purposes.
Mineral water trickled down a small wooden staircase on which the spring operator had placed items that he wanted to turn to stone. This practice was very popular at the time, as foreign visitors liked to take these encrustations home as souvenirs. If you would like to find out more about the petrification of objects, I would also recommend reading our article, ‘The sources of Saint-Nectaire‘ (coming soon).
One last spa season for the Croizat spring
A 1934 brochure intended for tourists visiting La Bourboule provides more information about life in the resort and the Croizat spring.
According to the brochure, the mineral composition of the spring is similar to that of the area’s other main thermal springs, such as the Choussy, Perrière and Fenestre springs. The latter produces cold thermal water. The document also emphasises the importance of the Croizat spring to the resort shortly before its pollution was discovered.
Page 3 mentions the flow rate of the main sources used by the resort.
A high flow rate indicates power and efficiency, and provides a marketing advantage. It creates the impression of abundant natural resources and superior quality. With a total flow rate of 740 litres per minute from the four main springs, a certain number of treatments could be offered each day, including baths, showers, and inhalations.
The Croizat spring alone supplied 200 litres per minute — the same flow rate as the Choussy and Perrière springs, which are the most important in the spa town.
Huge reservoirs were also used to store water flowing at night, to meet the service’s daily requirements. The Croizat spring had two reservoirs located north of the town (see map).
The Choussy and Perrière springs are both the result of artesian drilling, which caused the old springs to disappear. Their underground sources are almost adjacent to each other and two giant pumps bring the water to the surface at a total flow rate of 400 litres per minute. Once rivals, these two springs now supply the same water, originating from the same hot water deposit, but travelling through two separate pipes.
📗 A brief history of the spa resort’s origins
Originally a humble hamlet nestled in one of the Dordogne’s wildest valleys, La Bourboule could only be accessed via a steep road. The village comprised just a few houses, and its springs were only visited by locals.
In 1855, the springs provided only 35 litres of water per minute.
However, between 1863 and 1879, the resort experienced a boom during the ‘War of the Wells’. This conflict pitted the Choussy family, whose springs and spa establishment attracted most visitors and held a monopoly, against the municipality of La Bourboule, which was facing financial difficulties. The municipality sought to increase the number of municipal springs to boost thermal revenue through its concessionaire, the Viscount of Sédaiges, and the company he had set up.
War was declared. A series of increasingly deep drills were carried out, either to dry up the rival spring or to find new ones nearby.
By 1877, Sédaiges’ company was producing 632 litres of water per minute from its own springs. By 1879, it had emerged victorious from the ‘War of the Wells’. Exhausted and unwell, Dr Louis Choussy conceded defeat and died shortly after selling his properties to his competitors.
The brochure also highlights the mineral content of the springs. Like the flow rate, this is an important feature to highlight in advertisements. With 9.84 g/l, the Croizat spring is by far the most mineralised in the valley. This mineral water has a slightly salty taste. However, the mineral content may have changed since then.
Another noteworthy point is that, like the Choussy and Perrière springs, the Croizat spring is one of the world’s most arsenic-rich waters. All three springs contain high levels of arsenic, sodium chloride and bicarbonate, and they are all hot.
These striking phrases usually come before an extensive list of therapeutic properties (see page 4). Particular attention is given to the respiratory tract. You can also read our article, ‘How to Cleanse your lungs with simple, natural ways‘.
These brochures are published every season and list all the available entertainment (see pages 12–14).
Despite these similarities, recent studies have shown that there are probably three distinct hot water deposits in the Dordogne Valley: La Bourboule, Croizat and Mont-Dore.
The Croizat refreshment stands, in the past
Visitors can enjoy splendid views of the Dore mountains from the entrance to the Croizat spring site.
Following the path would lead you to a thermal refreshment room, which was extremely useful for the Compagnie des Eaux Minérales de la Bourboule (the spring’s operator at the time) and for patients who needed to drink the water. It was wonderful to watch people drinking the water and seeking health directly from the source.
This spring water was highly valued as a beverage due to its high mineral content (9.84 g per litre), which gave it therapeutic properties.
However, the remote location of the thermal refreshment stand, far from the spa town of La Bourboule, may have affected visitor numbers. In an urban setting, it would have been more likely to attract visitors seeking a pleasant spa experience.
Furthermore, there were no baths or showers on site, so it was not possible to enjoy spa treatments. In order to do so, you had to go where the water was transported.
The owner of these waters built a 3 km cast iron pipeline to the La Bourboule spa resort. Two large reservoirs were designed to collect water from the Croizat spring and supply three spa establishments with industrial equipment: Mabru, Choussy, and Les Grands Thermes. This included bathing rooms, showers, and thermal refreshment stands such as the one in the Grands Thermes’ entrance hall. One such stand was the Croizat refreshment stand.
This veritable palace, the most luxurious establishment in the resort, allowed visitors to sample the water from the Croizat spring for a small fee. The spring was undoubtedly famous at the time.
In this vestibule, visitors could shelter from the weather and relax (reading, chatting or resting) while enjoying a drink. Two young girls ran the refreshment stand and served water from the Croizat spring.
Bathing is usually not permitted.
In 1973, the commune of La Bourboule purchased the Croizat spring from the Compagnie des Eaux Minérales de La Bourboule. It now owns the site.
In February 2016, the commune of Mont-Dore (where the Croizat spring is located) issued a decree prohibiting access to the site. However, the ‘Sentier des Sources‘ (Springs Trail) remains accessible.
In 2021, the commune demolished the old infrastructure at the Croizat spring, including a bunker that had been built close to the gallery, as well as the outdoor pools. The locals then discreetly rebuilt the pools.
