Sometimes when we are having doubts, or do not know what to do, it feels like everything stops. You hit a metaphorical brick wall, not knowing where to go next. At times, you really physically stop. In English, you could say that you are at a stand or perhaps at a loss.
The Romans would instead say that the water stopped for them.
Cicero’s Stand
Cicero used this expression of water stopping for him as he wrote to his brother Quintus in May 56 B.C. He told Quintus that he did not attend the senate during a certain day as Campania (a region in southern Italy, surrounding Naples) was supposed to be discussed and:
“in hac causa mihi aqua haeret ”
— Cicero, Ep. Q. 2.7.2.2
i.e. “In this question the water stops for me.” (or: “In this question, I am at a stand.”)
The debate Cicero did not want to attend most likely had to do with Caesar’s distribution of public land in Campania, which had cost the republic a major source of income. This, however, is another story.
Cicero also used the expression in De Officiis, saying:
“sed aqua haeret, ut aiunt”
— Cicero, De officiis, lib III
Why Water?
But, why would Cicero say that the water stopped for him? What does water have to do with being in doubt?
Well, there are two explanations: The first is in allusion to water stopping in pipes or aqueducts. The idea is that just like pipes can be clogged up so that the water cannot get through and hence stops, so does your flow of thoughts at times – bringing them, and you, to a stop.
The second explanation has to do with time:
As the water in the expression stops, time or the flow of ideas stops. It is a common feeling that time stops when you are clueless as to what you should do next. You black out, you get stuck, or if you are Roman, your water stops.
The reason for the water to stop is simply explained by the fact that time in Rome was not rarely measured in water.
Clocks for the Court
In the more commonly known hourglasses, one measures time in sand, but there used to be clocks where water was used as well. The so-called water clocks were common in Greece, and due to the Romans’ fascination with the Greeks, they adopted the use of water clocks. There were several kinds and were regularly used in court proceedings.
Apuleius described one of these water clocks in his Metamorphoses:
“Sic rursum praeconis amplo boatu citatus, accusator quidam senior exsurgit et, ad dicendi spatium vasculo quodam in vicem coli graciliter fistulato ac per hoc guttatim defluo infusa aqua, ”
— Apuleius, Metamorphoses, lib. III
i.e. ”Next there was a loud shout of summons from the crier, and an elderly man stood up as speaker for the prosecution. In order to time his speech, water was poured into a small jar which had been finely pierced like a colander to let the water flow out drop by drop.” (transl. Hanson, 1996)
A loss of Water
As water was used to measure time, if you lost your water it meant the same as loosing your time. Hence Aquam perdo means to loose your time.
References
Apuleius. Metamorphoses (The Golden Ass), Volume I: Books 1–6. Edited and translated by J. Arthur Hanson, 1996.