Their bodies need water after they leave the Garden.
THEN God, merciful and gracious, looked upon them thus lying in the water, and nigh unto death, and sent an angel, who brought them out of the water, and laid them on the seashore as dead.
2 Then the angel went up to God, was welcome, and said, "O God, Thy creatures have breathed their last."
3 Then God sent His Word unto Adam and Eve, who raised them from their death.
4 And Adam said, after he was raised, "O God, while we were in the garden we did not require, or care for this water; but since we came to this land we cannot do without it."
5 Then God said to Adam, "While thou wast under My command and wast a bright angel, thou knewest not this water.
6 "But after that thou hast transgressed My commandment, thou canst not do without water, wherein to wash thy body and make it grow; for it is now like that of beasts, and is in want of water."
7 When Adam and Eve heard these words from God, they wept a bitter cry; and Adam entreated God to let him return into the garden, and look at it a second time.
8 But God said unto Adam, "I have made thee a promise; when that promise is fulfilled, I will bring thee back into the garden, thee and thy righteous seed."
9 And God ceased to commune with Adam.