Aslam

Praise be to Allah.This

question was answered for us by Shaykh ‘Abd-Allaah ibn Munayyi’, who

said:

“One

of the basic principles of sharee’ah is the hadeeth of the Messenger

(peace and blessings of Allaah

be upon him), who said: ‘There should be neither harming nor reciprocating

harm.’ Part of this principle is that the Muslim is not permitted to

harm himself, which includes not using contaminated water for doing

wudoo’.

So it

is forbidden to do wudoo’ using contaminated water, but if a person

does do wudoo’ using such water his wudoo’ is still valid, because it

is not naajis (ritually impure), but his action is haraam because he

is harming himself. And Allaah knows best.”