In the Trás-os-Montes region (Portugal), the termais of Carvalhelhos fails to meet the grandeur / popularity of it's cousins. One should note though, that the the hot springs of Chaves, Vidago and Pedro Salgadas are all conveniently located in the Rio Támega valley floor which with their natural accessibility has afforded them to expand to cater to outside visitors.
Carvalhelhos, located in the hills west of the Rio Támega, has had more opportunity to slowly evolve. Located just outside the village, the spa complex lies around a small stream within extensive forests. Just beyond the spa building the road crosses the stream there is a buvette. Despite the obvious lack of visitors, the buvette is manned and we are afforded a free glass of water. No need to sign a legal waiver here.
Apparently, development has only taken place from just before the last war and in part is stunted as the company running the thermal complex is more focused on bottling the water (bottler).
The Termasdeportugal website has this:
'Situated at an altitude of 800m de altitude, at the foot of a pre-Roman fort and surrounded by the leafy park of Serras do Barroso, Carvalhelhos spa (said to be holy due to their healing powers) provide a revitalising rest. The moderately mineralised water are indicated for restoring the body's natural balance and are particularly recommended for skin diseases and dermatological pathologies, digestive system and circulatory conditions'.
Unfortunately that is the extent of the info.
From this site, I learn that the water temperature is a lukewarm 22C, possibly not a hot spring? Wikipedia adds a couple of degrees and adds a Roman connection. It begs the question as to what Portugal accepts as thermal spring, anything above 20C?
Above shows the buvette. When we visited, a tired looking young chap reluctantly serves us a cup of water. Not hot.