The bounty

Misty 
The Azorean island of São Miguel has three geothermal zones, nicely distributed across the island from east to west. 

For the islands' central area of geothermaility, the hot spring(s) of Caldeira Velha are the showcase tourist attraction.  
Elsewhere in this zone there is the Caldeiras da Ribeira Grande hot spring with the many fumaroles nearby, as well as the geothermal power plant: Central Geotérmica do Pico Vermelho. 
All these are more or less related to the volcano of Fogo, who's water filled crater now entices visitors with the beautiful Lagoa do Fogo. 
That's if it hasn't disappeared in the fog. 

Like many of the São Miguels star attractions, the hot spring(s) of Caldeira Velha have seen some considerable improvements in the last few years, as European funding is increasingly determining the economic direction of the Azorean islands
This improvement is quite apparent at the roadside parking which is neatly folded into a sharp curve (lead photo above). And it's also packed with cars .... 

Such is the current day popularity of these hot springs that even this recently improved and expanded parking space is inadequate to house today's soakers. 

As the road to Caldeira Velha (from Ribeira Grande) and beyond is narrow and winding there's not much opportunity to park elsewhere, though we did find a forest park spot a couple of hundred meters uphill. 

This does not bode well for what seems a paradisian soak underneath a hot waterfall as that's what it's supposed to be. 

The entrance fee to the park like surroundings is a below par two Euro's (token fee?) and the chirpy entrance assistance bodes us a good soak. 

Entrance gate (right), your path to soaking (below).

Defeat
Beyond the entrance lies a well maintained pathway along a gabbling stream to a visitor center. 
Named Centro de Interpretacao Ambiental Caldeira Velha, the center essentially provides info on the natural circumstances of the protected area surrounding the stream and springs. It also acts as an educational (organizational) center.

Outside the building are the full center staff (no less than 4 persons) busily discussing events and ignoring the visitors. 

Inside the center is some explanation of the area and geothermality but a lot of long texts. Obviously a lot of effort put in.
Opposite the center is a hot spring area (see last photo of this blog) with the off-flow heading to a small but soaker lined hot pool. 

Knowing that there is also a hot waterfall, we continue the path uphill and 100 meters further upstream come to the waterfall. 
Great, time to change. 
Mental note of waterfall observation: not many slash nobody using waterfall / hot pool. Hmmm ..... 

Next to the visitor center were toilets (2 of them) and shower cubicles (2). Not extravagant, considering today's amount of visitors. 

But up here next to the waterfall are 3 changing cubicles which are a bit rustic. Essentially meant for the measurements of locals, it meant that the taller foreigners could peek over the edges to the neighbours cubicles which sort of defeats it's objective. Tss .... 

After changing, it's time to plunder the now deserted hot waterfall. 

Bummer.

It looks great, especially for the obligatory photo-op, but actually the waters are coolish. Cold. 

Well, not if one wades through to the waterfall proper: there the waters are just lukewarm, a minor improvement.

So abandon plan A. And plan B means a retreat down to the packed pool adjacent to the visitor center. 

This pool is a lot better soakingwise, though the temperature is just OK and the pool is not really that deep enough. Still it's natures bounty, can't complain about that.

Considerations
I do see that many a soaker just plump themselves in the waters with little thought for a pre-soak showering. 
Especially as the two shower stalls seem to be in high demand as most soakers shower after soaking. 
Though the absence of proper changing facilities may also have to something to do with the lack of showering. 
Would a shower pre-soak be helpful? I dare to say so as the outflows in the hot pool were not really very good; this no doubts raises questions about it's sanitary levels.

Though the center does not really have an own website, it does however maintain an active Facebook page with lots of photo's, both of the area as well as from other activities conducted from here. 
In a recent posting (November 30) it notes temperatures for the waterfall of 26,4ºC, while the smaller lower pool is 38ºC . 
In an even more recent posting, it states how the hot springs were closed foe a few weeks as the only road had been damaged during heavy weather.

As common with other hot springs on the island, there are many raving reviews, little though to add to the above.  
Tripadvisor notes that a visit here is no. 8 of things to do on São Miguel. Especially since the renovations there have been mostly consistently high notes. Some of the quotes from the reviews on Tripadvisor:

'Changing facilities are available, but expect to have to wait given that there are only a few stalls available'.
'If you see a big bus parked outside on the road when you arrive, consider seriously of coming at another time or day'.  
' ... the scenery was beautiful'.
'Totally disappointing. Feels like a tourist trap. It is a small place, but full of people. Parking could be a problem. The pool is so tiny, looks like a dirty jacuzzi filled with people such that it's hard even to move around'.
'Truly a very pleasant place. Beautiful nature with clean walkways'.

There's precious little other information available online. 
With one notable exception. Apparently the Portuguese speaking world are highly appreciative of a jump under the Caldeira Velha waterfall as a recent TV series (Jardins Proibidos) has a shot of the lead actors swimming naked under the falls, a practice which seems to be little copied and at the time might have been scandalous (source). And dubious because there were even body doubles .... 
But no such naughtiness on display now or even in the past ...