At the start of Blade Runner 2049, the protagonist, K, steps into his stark, Brutalist apartment and, weary from his job - hunting artificial intelligences masquerading as humans - he takes the shortest shower in cinematic history. Water blasts for half a second before cutting off. Outside, rain pours endlessly, drenching Los Angeles. It’s a grimly comical contrast: water, water everywhere, but fancy a power shower after a hard day's work? Whaddya think this is - the 20th Century?

Blade Runner’s dystopia is, as with much good sci-f, a reflection of the present. A future shaped by climate collapse but also by the strange contradictions we already live with, as anyone who’s endured a hosepipe ban during a sodden British summer could attest.

This confused relationship with our water supply was a central theme of a panel I chaired at the Good Home Alliance (GHA) conference at the British Library last month. I was joined by experts - Katie Smith from Defra, Cat Moncrief from CIWEM, Andrew Tucker from Thames Water, and Lutz Johnen from Aquality - to discuss housebuilding and water efficiency, a challenge both technical and cultural, wrapped in policy, infrastructure, and our own bad habits.

I was asked to chair the session because I’m editing a new industry guide on this very topic. Co-written by my PTE colleague Dr. Tom Dollard, it’s the second in our Designing for a Changing Climate series for the GHA, following our shading guidance published in 2023. This one tackles water efficiency, offering practical advice for new-build developers, architects, contractors, and their supply chains.

Water scarcity is core to the GHA’s mission with fostering a culture of water efficiency the first pledge in its manifesto. While it should be a concern for all of us a recent survey reveals how unaware we are of our own consumption. Asked how much water we each use daily, nearly half guessed about 20 litres - the answer is 142 litres. Regardless, we’re using too much. We need to reduce demand and think holistically.

That’s why Rachel Reeves recent announcement of several billion pounds in private sector funding to upgrade water infrastructure in support of the Oxford-Cambridge corridor - her vision for a British Silicon Valley - was encouraging. But this is where holistic thinking must come in. A thriving tech hub will need thousands of new homes. If it’s also to be a mooted AI powerhouse, it will require vast amounts of water - not for people, but for machines.

As The Washington Post reported last September, AI technology consumes huge volumes of water cooling data centres. A study found that a 100-word AI-generated email uses up 519ml - a typical bottle of water. Meanwhile a typical office worker sends 40 emails a day, so - well, you work it out. So, if you like your showers to last more than half a second, lay off the AI and write your own emails.

Look out for the guide in June - thanks for reading!