Counting What You Spend
You cannot manage a tradeoff you refuse to measure on both sides. The industry learned to obsess over power efficiency long before it learned to count water, and that lopsided attention produced a generation of buildings that looked green on a power dashboard while quietly draining stressed basins. Water use effectiveness and power use effectiveness are the two halves of one honest ledger, and reading either alone invites self-deception, because the cheapest way to improve one is often to worsen the other. The operators worth trusting report both, name their water source, and count the water burned at the power plant, not just the water that runs through their own pipes.
Knowledge check
Why can reporting only power efficiency mislead observers about a data center's real resource footprint?
Show the answer
Because the cheapest route to a low power-overhead number is often heavy evaporative cooling, which improves the power figure precisely by consuming large volumes of water, so a strong efficiency number can conceal, and even reward, a heavy water burden.