As for what exits through the urinary passage, it invalidates ablution, because it is most likely from the bladder.

As for what exits through the vaginal passage, the majority hold that it invalidates ablution. (1) Ibn Hazm said that it does not invalidate ablution, (2) stating that it is neither urine nor pre-seminal fluid. Whoever holds that it invalidates ablution must provide evidence; rather, it is like other waste matter that exits from the rest of the body. He did not mention anyone before him who held this view.

The view that it invalidates ablution is the more cautious one.

Thus, it is said: if it is continuous, then its ruling is that of urinary incontinence; that is, a woman purifies herself for the obligatory prayer after its time has begun, takes whatever precautions she can, and prays, without being affected by what comes out.

But if it ceases at a particular time before the prayer time expires, then she must wait until the time when it ceases arrives, for this is the ruling concerning urinary incontinence.

If someone were to ask: How can it invalidate ablution when it is pure?

The answer is that there is a parallel case: wind that exits from the anus invalidates ablution, despite being pure.

The leftover water from which a cat has drunk, and that of animals smaller than it in physical size, is pure.

His statement, “The leftover water from which a cat has drunk, and that of animals smaller than it in physical size, is pure”: leftover water