Is it ok to make Wudu without taking off the Hijab?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Performing ablution without taking off the Hijaab is related to two of the obligatory parts of ablution: washing the face and wiping over the head. So, if a woman can wash her face; i.e., pour water from the top of the forehead to the bottom of the jaw, and from one ear to the other, and wipe her head with her hand, or wipe over her head's cover which is spread under chin and being worn in the state of purity; then a woman's ablution is valid. But if it is not possible to wash the face as mentioned above, or the head cover has been worn before having performed ablution prior to this, or it is easy to take it off, then it is not permissible to wipe over it (the head's cover). Such an ablution is invalid.

Also, it is necessary to take off the head cover.

For more benefit on the nullifiers of ablution, please refer to Fatwa 84093.

For more benefit on the detailed description of ablution, please refer to Fataawa 82845 and 83164.

Allah knows best.