slms if a person needs ghusl and there is no water and he goes to work and zuhr approaches, what must he do?(there is water for wudhu)

If he is in need of an obligatory ghusl (bath) and water is not available within a radius of one mile, then he may make tayammum with the intention of obligatory Ghusl. However, if he finds water before performing Salaat, then he should take a bath with this water.

If Dhuhr Salaat approaches, then he must first perform Salaat and then you should go to work. Whatever amount of water is there, he should save it and utilise it for Wudhu. (Nurul idhaah pg.42)

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai