Auvergne has the largest regional park in France. It is a unique landscape of grassy lava domes, cinder cones and low-level vents or explosion craters. Through it passes the Route des Villes d'Eaux beneath which the world's best-quality natural mineral water has been naturally filtered since the Miocene age.
The 17-station "Water Route" takes you and your overworked kidneys through four departments to France's most famous spa towns to enjoy their much-sung curative waters at source. The Auvergne leg takes two days. Mainly because of the frequent comfort stops.
En route are the ancient thermal spring towns of La Bourboule, the 28-spring Chatel-Guyon and its Les Gargouilloux - gurgling waters, the 100,000 litres an hour, 32.5C Eugenie spa at Royat, and silica-rich Le Mont-Dore.
Facilities on offer include hamman, mobility pools, subcutaneous gas injections, mud applications and "pharyngal nose showers", as well as "humage", in which you inhale hydrogen sulphide through a fighter pilot's mask.
All the breathing workshops and strengthening your respiratory mucosa that inhibit the diffusion of allergens builds up a thirst.
Most bottling plants offer degustations. At Volvic, this happened by a dark wet grotto by a loading bay. Here I heard from a passionate hydrologist that the Calivic spring was discovered in 1927 and Volvic was first bottled in 1938. One billion bottles are now produced every year.
With 1200 known springs, France is the world's leading mineral-water producer. However, Germany markets more than 400 types of mineral water compared to France's 50.
I also learned that we consume 2.5l of it every day and we renew our body water every 10 days, a tenth of it through swallowing our own saliva.
Vichy is still the best-known spa, with curistes taking la medicine douce every day at the fountains in the grandly colonnaded Halles des Sources, where the beau monde of the 19th century went to detox and French colonials were sent to cure themselves of the tropics. The thermal baths were built as a toy for the daughter of Louis XVI.
By the time I returned to Volvic, I was enjoying optimal renal function and felt effervescent.
Monsieur le Maire was still holding court in Le Tilt. "An autre?" he asked, looking towards the bartop taps, suspecting I might like something to wash away the taste of hardened magma. And needed something that wasn't calorie-free.
I shared a welcome and delicious dehydrating thirst-quencher with Monsieur.
Water consumption is all about temperance. Which is always advisable. But in moderation.
Checklist
GETTING THERE
Emirates flies daily from Auckland to Lyon, via Dubai, from $2664, Economy Class return. emirates.com
DETAILS
For information on the United Nation's World Water Day projects,
go to unwater.org/worldwaterday.