leaky/leaking pipe

"Leaky" is an adjective which describes a permanent or long lasting attribute of a thing whereas "leaking" is a gerund or present participle which implies a behaviour or action which is in the present, and has only recently started.

I replaced my leaky old bath with a new one.

My roof is leaky but I cannot afford to repair it.

"Hello? Is that Acme Plumbing Company? I need your help! A pipe is leaking in my house!"

Sieves are leaky, but my roof is leaking.

Hi Contrex

Once again, many thanks for your guidance.

Just to confirm: The plumber repaired the leaking pipe yesterday is correct if the leaking has just started.

The plumber repaired the leaky pipe yesterday means that the pipe has been leaking for some or a long time.

Many thanks.

That is correct, but don't expect all native speakers to be aware of the distinction! (Or even agree!)

Of course, a leaking pipe is also leaky. The first is an action, the second is a quality. Perhaps that is the best way to describe the difference. A leaky roof is not always leaking, but a leaking roof is definitely leaky!

Hi Contrex

I agree with your explanation.

A leaky roof is not always leaking, but a leaking roof is definitely leaky! This sentence clearly explains the difference.

Many thanks.

Any rule that we describe, Contrex, describes how people use language. You're right that many, even most are not consciously aware of these differences/nuances but every speaker "knows" them nevertheless.

That's one good way to tell the difference between a prescription and a description. The first, people never follow when using language naturally. The latter is simply, language.