English is not my first language and I'm having trouble using the words "leak" and "leakage". Do they both mean the same thing? or what is the correct grammatical usage of each word?

Thank you very nice people :)

  • You might want to check out English Language Learners, a site designed for people who have questions because English is not their first language. (This question may get migrated there, or it may get answered here, so I wouldn't ask it on ELL right away.) Also, I don't mean to say you're not welcome here on ELU – you are.
    – J.R.
    Dec 8, 2014 at 12:16
  • This would appear to be a borderline question as there are native English speakers who are not clear on this distinction as well. :)
    – Hershel
    Dec 8, 2014 at 13:00
  • In my opinion a leak is a hole, the leakage is the water that runs through it. Dec 8, 2014 at 19:06
  • Also, euphemism for urination: “he had to take a leak” (noun)
    – Misti
    Dec 8, 2014 at 19:19

2 Answers 2


The word "leak" can be a noun or a verb, but "leakage" is only a noun, so that's one difference.

When used as nouns the two words can have the same meaning, i.e. "an act or instance of leaking" or "any means of unintended entrance or escape."

The word "leak," however, can also have another meaning which is not relevant to the word "leakage" and that meaning is "an unintended hole, crack, or the like, through which liquid, gas, light, etc., enters or escapes."

The word "leakage" also has another meaning which is not relevant to "leak" and that is "something that leaks in or out."

As someone wrote on this forum thread, put very simply: "a leak is a hole, the leakage is the water that runs through it."


The definitions of the terms used in this procedure are:

  • A leak is the quantity of fluid that comes out of a component that is sufficient to become a drop or drops, or will possibly become a drop (approximately 20 drops = 1 cc, 75600 drops = 1 gallon)
  • A leakage is a quantity of fluid on the surface of a component that is not sufficient to become a drop
  • A stain is an area on the surface of a component that has a different color. It is usually caused when fluid leakage dries on the component surface after high temperature operation.
  • 3
    Hello, Andrii. Where did you find this, please? You will see that other answers tell a different tale. They are closer to dictionary definitions. Almost certainly what you have found here are stipulative definitions chosen by some institution or company, which 99+% of practised Anglophones will not be aware of and do not use. As such, this answer will only be helpful if that fact is pointed out (and possibly not even then, as normal usages are more important for almost all people). Mar 20, 2021 at 18:26

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