Say, "Have you considered: if your water was to become sunken [into the earth], then who could bring you flowing water?"
The Saheeh International Quran Translation
قُلْ أَرَءَيْتُمْ إِنْ أَصْبَحَ مَآؤُكُمْ غَوْرًا فَمَن يَأْتِيكُم بِمَآءٍ مَّعِينٍۭSay, "Have you considered: if your water was to become sunken [into the earth], then who could bring you flowing water?"