Many metal–organic frameworks (MOFs) that would otherwise be good candidates for sorption-based atmospheric water harvesting (SAWH) are not stable in moisture. Water molecules can disrupt the coordination bonds that hold the framework together. However, MOFs constructed from the Cu paddle-wheel unit are a curious case, because whereas most are not water-stable, a few are. Now writing in Chemical Communications, researchers discovered that MOFs with multiple hydrogen-bonding sites spaced around the Cu paddle-wheel bind to the incoming water molecules. This water is essentially handcuffed within the pores and cannot attack the sensitive bonds. In addition, the immobilized water attracts more water through hydrogen bonds, raising the MOF’s water affinity. The team tested the MOF in a SAWH setup, demonstrating its impressive water sorption capacity, ease of regeneration and, of course, excellent stability. The clarified role of hydrogen-bonding sites in these MOFs may be a thread to designing better materials for SAWH.