Two people were rescued from the river at Chantry Bridge in Wakefield.
A female had entered the water and got into difficulty and a man passing by had followed to try to help her.
Emergency services attended and the pair were rescued at around 6.50pm on Monday.
A spokesperson for Wakefield Fire Station said: “The lady had got into the river and a passer by had risked himself by entering the water to assist her.
“He grabbed hold of her and kept her above the water while somebody called for us.
“Several crews attended and managed to get some ladders in and get them both out to safety.
“The lady was in the water for about 15 to 20 minutes so she was likely to be suffering the effects of the cold.”