Aquistas

Waters
Portugal boasts it's fair share of thermal hot springs. Though wikipedia seems to be oblivious to this, Termas de Portugal counts 38 termas (Portuguese for hot spring) as it's members, a figure the excellent (but Portuguese language only) Águas Termais attributes as those hot springs for which commercial concessionaires exist.

The former adds a number of now dried up geothermal springs, as well as partial geothermal and quite a list of commercial mineral water bottlers. For one thing has become apparent on my visit to the Portuguese termas, and that is the fact that the Portuguese like their waters ...

(Do note though that confusingly the area around Furnas on the Azores island of Saõ Miguel counts no less than 22 hot springs, none of which were counted in the above mentioned ....).

Certified
Portugal and hot springs go back a long way and it seems that like many of the other European cultures the Portuguese prefer the medical benefits of thermal waters. Sod the socializing.

Thus it has seen fit to transform their natural springs to scenes of medical dedication. Such that if you would even remotely dare to take a soak, a doctor will have to certify whether or not that need be the case. Naturally forking out 50€ or so, just to be told that "yes, you can take a soak" seems to fend off the touristy type, in need of a one-off soak, the hippy or the novice.
What remains are a geriatric generation who do need to heed the doctors advice, who stand to benefit most from the waters and whom have the freetime to say use the advice taken to stay for a week or two of great soaking ...

Even the art of sampling the waters with a couple of sips will sometimes require a signature from yourself absolving the termas of any liability in case you just might keel over or die. Or less.

Aquistas of Chaves
Any road, one of the 38 concessions mentioned in the first paragraph lies in the town of Chaves, Vila Real district, glued to the northern border with Spain. Serving the wider mountain region, Chaves (pronounced as chaaves, as in chives) has seen quite some historical turnovers leaving it with a long Roman bridge and a number of forts and towers which in some time had managed to either keep conquerers at bay or dissuade would-be liberators from freeing the town.

Naturally, it lies along the banks of stealthly slow flowing Rio Tamagas and boasts of it's bathing waters. Well, this blog will see if the boasting is fair!

Chaves by night

The wider region of Chaves though, to it's credit, does mention in the local tourist brochure, an upswing in aquistas (persons who undergo medical treatment by bathing in thermal baths). The upswing is thought to be due to the increased awareness to health and well-being. Unfortunately the brochure (produced by the Alto Tamega e Barroso tourism office) is undated and also unsubstantiates this trend.
Specifically it adds for the termas of Chaves:

'The medicinal properties of the thermal Spa of Chaves were discovered by the Romans, and soon became an ex-libris of the city. They are the most accredited spas in Portugal, having the hottest thermal waters of Europe. All year round they are visited by thousands of people finding treatment for rhuematism, nutrition diseases (obesity[!], gout and diabetes), disorders of the liver, intestines and hypertension'.

Operator Termas de Chaves supposedly (poor translation?) adds on it's Portugese language website that the waters are unique for the Iberian peninsula and facilities are geared to receive 15,000 'patients'.

Then the charges:

• just 35€ for the doc, 
• but then 30€ signage fee and 
• another 20€ for nutionist.

That´s just €85. Oh, and then if taking a soak, add the mere €5,50 to that figure.

Sourced
Other excellent info from the Wikipedia Chaves entry:

'The hot springs (Portuguese: Caldas) were known since the Roman period, when the town was Aquae Flaviae; the Waters of Flavius were an important social gathering point, but fell into disuse as the town was slowly abandoned by attacks.

...

The waters of the spring, that are captured in three springs within Chaves, have mean temperatures of 73 °C (163 °F) (the hottest bicarbonate waters in Europe). The modern spa industry in Chaves use these waters for numerous treatments, including stomach, liver, intestinal, and kidney ailments, through oral ingestion. Many small guesthouses in the old part of the town are dependent on the influx of these visitors. The thermal spas are located between the castle and the river, in front of a large area of grass-covered park with playgrounds and tennis courts'.

There is actually an archeological dig in the center of Chaves not too far away from the hot spring, in line with the bridge which should contain remains of some original roman spa, but as there was a high fence around it, can't verify this ...

Flickr member frproart has a number of photo's before the fence was constructed.

The spring in the old days, possibly before WWII. Source

Sampling the soaking source
So I skipped the soaking part, but decided to nose around. Besides the intense medicalisation of soaking process here, another aspect of Portuguese hot spring culture is the ability to sample the waters by drinking. Thermal springs of the official kind cater to the vox populi: free glasses of water.

 

Fill her up please. Inside the Termas de Chaves buvette

In a building alongside the spa there is a nurse like figure doling out plastic cups of water straight from a tap, we hope that's connected to the hot spring. The water is not hot and has little taste. To fully appreciate the flavour of this plastic cup of water, there a number of chairs and benches, mostly occupied by the elder part of the globes population. There's not much I can say about the water though I do like this tradition, a buvette [refreshment stall] along the soaking facilities.

Outside the buvette is supposedly one of the aforementioned three sources. Steam rises up with a faint smell of sulphur; the only actual hint that something geothermal was apparent.

 The source

So you may have guessed, I didn't soak at all.

And from the lack of sources, neither have many other netizens ...