Question Summary:
Does water need to reach inside the nails? i.e if someone has dirt e.t.c under their nails would their Wudhu be valid?

Question Detail:

Does water need to reach inside the nails? i.e if someone has dirt e.t.c under their nails would their Wudhu be valid?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
In principle, it is Wajib (necessary) for one to pass water inside one’s nails.[1]
If the substance is such that it prevents water from reaching the area inside one’s nails, one’s Wudhu is invalid and would have to be repeated.
If the substance is such that it does not prevent water from reaching the area inside one’s nails, one’s Wudhu is valid and intact.[2]
And Allah Ta’āla Knows Best
Moulana Ismail Desai,
Student Darul Iftaa
Durban, South Africa
Checked and Approved by,
Mufti Ebrahim Desai.