Is drinking water after meals a sunnat or not?
A: Allāmah Ibnul Qayyim rehmatullāh ῾alayh has mentioned that the habit of Nabi [SAW] was of not to drink immediately after eating as this is harmful to the digestion process. However, if there is a pressing need to drink immediately after that, then only drink enough to quench the thirst. One may then drink after some time elapses. NOTE: This elapsed time is estimated to be 20-30 minutes.
(Zādul Ma῾ād, Vol. 3, Pg. 114)