1. The water we use for Wudhu must be clean. (Wudhu performed with water that is najis is void.)
2. The water must be pure. (Wudhu performed with water that is mixed is void.)
3. The water must be lawful to use. (Wudhu performed with water that is stolen or one does not have the permission to use is void.)
4. The container that the water is in must be permissible to use. (Wudhu performed with water that is in a stolen container or without the permission of the owner is void.)
5. The container that the water is in must not be made of gold or silver.
6. The parts of. the body that must be washed and wiped in Wudhu, must be clean (not have najasat on them).
7. There must be enough time to perform Wudhu and Salat.
8. The Wudhu must be performed with the intention of seeking nearness to Allah (SWT) and for His pleasure.
9. The Wudhu must be performed in the order that was mentioned (Tartib).
10. The actions in Wudhu must be performed one after another with no time gaps between them (Muwalat).
11. The person himself must perform the actions in Wudhu (washing his hands and face, and wiping his head and feet) and he must not get help from others.
12. There must be no problem or harm for one by using water.
13. The parts of the body where the water is applied must not contain anything that would prevent the water from reaching that area.
source : http://www.maaref-foundation.com/
