Reference: Fataawa Ramadhaan – Volume 2, Page 537, Fatwa No. 511
Majmoo’ Fataawa ash-Shaykh ‘Abdul-‘Azeez bin ‘Abdullaah bin Baaz – Volume 3, Page 252
Question: A man who was fasting took a bath and due to the strong pressure of the water, he ended up swallowing some water without intending to. Does he have to make this fast up?
Response: He does not have to make this fast up because he hadn’t intended that, so his ruling is that of one who is forced and one who has forgotten.