"Time, as it Evaporates . . .", a translation by Jean-Louis Trudel of "Le temps, en s'évaporant", a short story by Jean-Claude Dunyach. You may have read it in the anthology Year's Best SF 10 (Kathryn Cramer and David G. Hartwell, eds.), which can be "borrowed" (for free but registration required) from the Internet Archive. Here is a Goodreads review by Lizabeth Tucker:
When time rips apart, only one small Muslim town survives in a pocket caused by surrounding mountains. But that time [lake] is slowly receding. So incredibly deep. Faith and humanity, love and hate, all have a place in this tale.
[The following confirmation was added by user Valorum with an excerpt from the story, which is partly available at Google Books.]
Writing is erased when it leaves the time liquid:
On the other side of the lake’s frosted glass lies a Universe without time. Marwan is the only one to have seen it; the superstitious dread which prevents other community members from venturing to the stairway’s top has allowed him to enjoy an unchallenged prestige. If someone dared to climb as high as him, he would see that the emerged peak of the minaret is clear of any inscription. The name of the Lord is erased as soon as the time-level falls, the earthenware tiles recovering their virginity temporarily violated by the touch of faith.
A few months earlier, Marwan carved the names of all the gods he knew on a clay tablet attached to the end of a stick. The tablet was destroyed when it pierced the surface, and the muezzin recovered his serenity, only shaken for a time. In this world as in the other, no one is greater than Allah.