David Sedlak

David Sedlak did not set out to write the books that made him one of water’s most-read voices. He is a chemist by training, with a PhD in water chemistry from the University of Wisconsin-Madison, and for years his Berkeley lab was busy with something narrower and less glamorous: tracking where pharmaceuticals and steroid hormones end up when we recycle water and send it back to the tap. What surprised him was not the chemistry, it was the public. He kept meeting people who had no idea where their water came from, and then he realised that we, the water professionals, do not really know either. That gap is what started the writing.

David Sedlak’s first book, “Water 4.0”, came out of that realisation, and it told the story of our water systems as four big reinventions, from Roman aqueducts to drinking-water treatment to sewage treatment to the reuse era we are entering now. The point he kept circling is that water professionals behave like the blind men and the elephant: each of us understands our own piece, the pipes or the membranes or the financing or the policy, and almost nobody holds the whole animal in their head at once. The fix he argues for is “one water”, the unfashionable idea that you cannot solve drinking water, wastewater, stormwater and reuse as separate problems, because physically they are the same water moving through the same city.

David Sedlak’s second book, “Water for All”, widened the lens because he felt the first one had quietly been a book about water for rich people who live in cities. This one takes on the harder global question, the six water crises he organises the book around: water for the wealthy, for the many, for the unconnected, for good health, for food, and for ecosystems. And his honesty about it is the tell of how he thinks, because he admits none of us are really qualified to understand the full depth of the global water challenge, himself included, which is exactly why he wrote it as, in his words, his own homework.

David Sedlak is not just an author, and this is the part people miss. Both books were written alongside two of the biggest research bets in American water. While drafting “Water 4.0” he was launching ReNUWIt, the National Science Foundation centre for Reinventing the Nation’s Urban Water Infrastructure, and “Water for All” coincided with the launch of NAWI, the Department of Energy’s National Alliance for Water Innovation, the desalination hub he chairs the research council for. So when he talks about how water technology actually matures, he is talking from inside the machine, and his core warning is sobering for anyone expecting fast wins: in water, the road from a clever invention to a technology you take for granted is measured in decades, not years. You can hear the whole argument in his conversation on the six water crises.

David Sedlak’s real obsession, though, is not any single technology. He thinks the water system we have today will undergo dramatic change in the next three decades whether we plan for it or not, and that our worst habit is patching a problem only once the public decides it is a crisis. So what he is genuinely trying to build is not a gadget but a generation of people who can think holistically, and he describes the payoff with a metaphor only a chemist would reach for:

“I’d like to think about it the way a chemical engineer thinks about a catalyst. A catalyst doesn’t get depleted by the reaction it undergoes. It keeps working and working and working. The human capacity that we create lives on beyond any small research program we do, and hopefully it diffuses out and influences others.”

He is, in short, the rare water scientist who would rather change how the field thinks than sell it a single answer, which is most of why two of his books sit on so many water professionals’ shelves.