Water from lakes, not properly contained (5)

I believe the answer is:

leaks

I'm a little stuck... Click here to teach me about this clue!

Here is my best explanation:

'water from' is the definition.
I can't judge whether this definition defines the answer.

'lakes not properly contained' is the wordplay.
'lakes' anagrams to 'LEAKS'.
Though, I'm not clear how the anagram is indicated.

Can you help me to learn more?

This clue was last seen in Evening Standard