The most official water costs $120k a gallon

most needs for such water are for calibration of instruments - many labs run stable isotopes measurements which has many applications from tracing how plants use water to measuring your metabolic base rate .. so the main use case it to calibrate instruments because it's really difficult to have an absolute measurement of stable isotope ratios from first principles - and the ratios are so small you typically express them in relation to standards like VSMOW

Reminds of me of the "most expensive peanut butter" at ~$2.44/g - sold by NIST, I assume for some sort of peanut butter factory process calibration: https://shop.nist.gov/ccrz__ProductDetails?sku=2387

A US gallon of deuterium water costs roughly $2,600 to $3,800, while a gallon of pure tritium water (super-heavy water) would cost about $44 million.

Interesting article but left me wondering why they don't use ¹H₂¹⁶O as the "standard water"? Surely you can make that (relatively) easily in a centrifuge by spinning out the lightest fraction of water.

This is why we should ditch Celsius for Kelvin. I never liked how we coupled 0 and 100 to where water freezes and boils under certain conditions. Kelvin doesn't rely on non-invariant reference points.

How does the water taste?

Loved reading this. Thank you!

gallon is not a si unit ;)

As specialized world-class lab supplies and reagents go, that is not very expensive. Stuff like pure Xe (for space thrusters) can be more by mass.

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