The default is that anything that exits from either private parts nullifies ritual ablutions (wudu), for both men and women. Such things are also considered in themselves ritually impure (najis). [Haskafi, Durr al-Mukhtar, Bab al-Ghusl]
This includes all female discharge, except one type. The discharge that does not nullify ritual ablutions (wudu) and is considered ritually clean (tahir) is the chronic vaginal discharge (rutubat al-farj) that comes out normally and regularly, and is clear and not discolored. Some scholars explain it to be akin to the sweating of the vaginal walls. When reasonably possible, one should renew one’s ritual ablutions in such cases. However, when it is difficult to do so, such as at work or school, there is nothing wrong with following this ruling. It is what is indicated by the words of Ibn Abidin, as confirmed by the fuqaha.
It should be noted, again, though that all other discharge, even if slightly discolored, nullifies ritual ablutions and is ritually impure.
