The wettest countries don't live the longest
The driest countries on Earth are some of the longest-lived.
Put renewable freshwater per person on one axis and life expectancy on the other, across the 180 countries with both numbers, and you'd expect water — the stuff of life — to pull longevity up with it. It doesn't. There's almost no relationship at all — the correlation is about +0.02. The scatter is a shapeless cloud. How much water nature hands a country tells you essentially nothing about how long its people live.
Look at the extremes
At the dry end, where there's almost no renewable water at all, sit some of the highest lifespans on the planet: Kuwait (84.6 years, 0.0 m³ each), Singapore (83.3 years, 106 m³ each), Israel (83.2 years, 80.0 m³ each). At the wet end, soaked in renewable water, sit some of the lowest: Central African Republic (57.7 years, 27,658 m³ each), Guinea (60.9 years, 16,080 m³ each), Sierra Leone (62.0 years, 19,331 m³ each). One column has thousands of times the water of the other and lives a quarter-century less. If water in the ground decided lifespans, this table would be upside down.
So what does decide it?
Water you can actually drink. Swap raw availability for safely managed drinking water — the share of people with clean water on premises — and the shapeless cloud snaps into a line. That correlation with life expectancy is strong, about +0.85. The thing that shows up in a lifespan isn't how much water falls on a country; it's whether the water reaching people is clean.
And clean water mostly tracks one thing: money. Life expectancy against GDP per person runs at about +0.85 — just as strong as the drinking-water line, because they're two views of the same engine. Wealth builds the treatment plants and the pipes, the pipes deliver the clean water, and the clean water is one of the reasons rich countries live longer. The Gulf states make the point at full volume: almost no natural water, near-universal safe access, lifespans in the eighties, all of it bought.
The lesson, again
This is the same trap as the per-capita reorder, wearing different clothes. A big number for a natural resource feels like security, and it isn't. The Central African Republic has more renewable water per person than almost anywhere, and a life expectancy that would have been ordinary in 1950. Availability isn't security; security is delivery. You can read both ends of it yourself — water per person against lifespan in the comparison, or build any pairing you like in the console. The cloud is a cloud. The staircase is clean water.