The number of Mexican states exposed to high water stress will almost double to 20 by 2050, from 11 in 2020, under all scenarios covered in our analysis, without adaptation measures. States facing the greatest risk are already short of water and may experience decreased economic growth as the frequency and intensity of droughts increase. An increase in investments in water infrastructure over the long term could weaken some states' and municipalities' budgetary performance and result in higher debt, but go some way to building resilience to water scarcity.