What is the authenticity of attributing the saying: "Praise be to Allah, who made this water fresh and palatable, and did not make it salty and bitter because of our sins" to the Prophet, may Allah bless him and grant him peace, after drinking water? And is it permissible to say it even if it is not authentic?

The Hadith: "Praise be to Allah, Who has given us sweet, fresh water to drink by His mercy, and did not make it salty and bitter because of our sins," is very weak and not authentically attributed to the Prophet (marfu'). Its chain of narration includes Jabir Al-Ju'fi, who is accused of lying, and it is also mursal (has a missing link at the beginning of the chain). It was also narrated by Ibn Abd Al-Hadi from Ibn Juraij from Ibn Khuthaym as marfu', but it is mursal, and Ibn Juraij is a mudallis (one who practices tadlis, concealing defects in a hadith chain) who narrated it using 'an'ana (saying "on the authority of" without explicitly stating he heard it directly). As for the saying of Al-Hasan Al-Basri: "That Al-Hasan used to say that when he drank water," its chain of narration from him is authentic. There is no harm in occasionally reciting this remembrance, without believing it to be authentically established as a Sunnah from the Prophet, peace and blessings be upon him, or consistently observing it as one observes Sunnahs.