Said "Get me water" (3)
I believe the answer is:
sea
'me water' is the definition.
'sea' can be an answer for 'water' (sea is a kind of water). I'm unsure of the 'me' bit.
'said get' is the wordplay.
'said' indicates a 'sounds like' (homophone) clue.
'get' becomes 'see' (I've seen this before).
'see' is a homophone of 'SEA'.
Can you help me to learn more?
(Other definitions for sea that I've seen before include "Cod's home?" , "It's stocked with fish" , "eg Dead, Red" , "Body of saltwater" , "Expanse of salt water" .)