Charles Ellicott Commentary Exodus 7:23

"And Pharaoh turned and went into his house, neither did he lay even this to heart." — Exodus 7:23 (ASV)

Neither did he set his heart to this also. —Hebrew, Neither did he set his heart (i.e., pay attention) even to this. Pharaoh did not take even this to heart.

He passed it over as a slight matter, unworthy of much thought, and turned, and went into his house. Probably care was taken to keep him constantly supplied with the well water, which, however brackish, would be sufficient for his customary ablutions. He drank, no doubt, a more generous liquid.