So, it turned out that, instead of doing useful things, for example, grinding grains, water was “ground”. It is as useless as carrying water in a sieve. There are other variants of the origin of the phrase. For example, Vladimir Dal, author of the ‘Dictionary of the Russian language’, wrote that, in the old days, monks were forced to grind water as a punishment. And, in the monasteries, this measure migrated from ancient writings, understood very literally.