Praise be to Allah.
What is well-known is that the scholars say that everything that is discharged from the front and back passages is naajis (impure) except for one thing, semen, which is taahir (pure); apart from that everything else that has substance is naajis and breaks one’s wudoo’. On this basis, whatever fluid comes out of a woman is naajis and requires her to renew her wudoo’. This is what I understand after researching the issue with some scholars and consulting reference material. However, I did not feel entirely comfortable about this issue, because some women always have this discharge; if this is the case, then she should handle it as incontinence is handled: if she has wudoo’ she should wash her private parts when the time for prayer comes, and be careful not to let the urine contaminate her. This is similar to the advice that the Prophet gave to the woman suffering from istihaadah (abnormal non-menstrual bleeding).
Having also discussed the matter with some doctors, it is clear that if the discharge is from the bladder, the woman should do as described above; if it is from the vagina then she must perform wudoo’ because of it, but the discharge is taahir and she does not have to wash her clothes if it gets on them.