Water filling everything in ranch? It’s nothing to worry about (5,5)
I believe the answer is:
false alarm
'it's nothing to worry about' is the definition.
(a warning which you needn't have worried about)
'water filling everything in ranch?' is the wordplay.
'water' becomes 'sea' (the sea is water).
'filling' is an insertion indicator.
'everything' becomes 'all' (all things).
'in' means one lot of letters goes inside another.
'ranch?' becomes 'farm' (ranch is a kind of farm).
'sea' going into 'all' is 'alseal'.
'alseal' going inside 'farm' is 'FALSE ALARM'.
(Other definitions for false alarm that I've seen before include "Panic over" , "Warning proving unnecessary" , "unfounded scare?" .)