i have one litre water. can i use this water for wudhu befor shalah. how much water minimize we use for wudhu

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

One litre of water is sufficient for performing ablution; rather a Mudd (which equals 0,688 litre) is enough. It is confirmed that the Prophet used to perform ablution only using one Mudd and would perform Ghusl (ritual bath) using one Saa' (which equals 4 Mudds), as reported by Al-Bukhari and Muslim . Therefore, whoever uses a Mudd properly in ablution; it will be enough for him.

As regards the minimum quantity of water which is sufficient for ablution, then most of the scholars are of the view that there is no minimum quantity of water. What should be considered is that the limbs which must be washed in ablution are washed. Therefore, if a person performs ablution and washes all the limbs that should be washed in ablution even with a quantity lesser than a Mudd, then his ablution is acceptable. Indeed it is confirmed that the Prophet performed ablution with a third of a Mudd. [Al-Haakim].

Ibn Qudaamah said: “This is the view of Ash-Shaafi'i and the view of the majority of the scholars .”

However, some scholars are of the view that less than a Mudd is not sufficient as the Prophet said: “A Mudd is enough for ablution and a Saa' is enough for Ghusl.” [Ahmad and Ibn Maajah]. According to this view, the narration sets the estimation of the quantity of water which is sufficient for ablution and that anything less than that is not sufficient.

Anyway, according to both views, if the limbs that must be washed in ablution are not properly washed with a Mudd, and there is a need for more water, then it is acceptable as long as there is no extravagancy.   

Allaah Knows best.